> For the complete documentation index, see [llms.txt](https://docs.apryse.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.apryse.com/core/digital-signature/sign-pdf.md).
# Sign a PDF document on Server/Desktop
Learn how to digitally sign PDF files using the Apryse SDK. Add approval signatures with a Digital Certificate for authenticity and security. Full code sample provided. The Apryse Server SDK streamlin
{% hint style="info" %}
**Requirements**
*These packages are required to use these features in production. Trial keys have unlimited access to all features*
Package: Digital SignatureLive demo
{% endhint %}
To sign an existing approval signature field in a PDF Document:
{% tabs %}
{% tab title="C#" %}
{% code lineNumbers="true" %}
```csharp
using (PDFDoc doc = new PDFDoc(docpath))
{
// Retrieve the unsigned approval signature field.
Field found_approval_field = doc.GetField(approval_field_name);
DigitalSignatureField approval_digsig_field = new DigitalSignatureField(found_approval_field);
// (OPTIONAL) Add more information to the signature dictionary.
approval_digsig_field.SetLocation("Vancouver, BC");
approval_digsig_field.SetReason("Document approval.");
approval_digsig_field.SetContactInfo("www.apryse.com");
// (OPTIONAL) Add an appearance to the signature field.
Image img = Image.Create(doc, appearance_img_path);
SignatureWidget approval_signature_widget = new SignatureWidget(found_approval_field.GetSDFObj());
approval_signature_widget.CreateSignatureAppearance(img);
// Prepare the signature and signature handler for signing.
approval_digsig_field.SignOnNextSave(private_key_file_path, keyfile_password);
// The actual approval signing will be done during the following incremental save operation.
doc.Save(outpath, SDFDoc.SaveOptions.e_incremental);
}
```
{% endcode %}
{% endtab %}
{% tab title="C++" %}
{% code lineNumbers="true" %}
```cpp
PDFDoc doc(docpath);
// Retrieve the unsigned approval signature field.
Field found_approval_field(doc.GetField(approval_field_name));
PDF::DigitalSignatureField approval_digsig_field(found_approval_field);
// (OPTIONAL) Add more information to the signature dictionary.
approval_digsig_field.SetLocation("Vancouver, BC");
approval_digsig_field.SetReason("Document approval.");
approval_digsig_field.SetContactInfo("www.apryse.com");
// (OPTIONAL) Add an appearance to the signature field.
PDF::Image img = PDF::Image::Create(doc, appearance_img_path);
Annots::SignatureWidget approval_signature_widget(found_approval_field.GetSDFObj());
approval_signature_widget.CreateSignatureAppearance(img);
// Prepare the signature and signature handler for signing.
approval_digsig_field.SignOnNextSave(private_key_file_path, keyfile_password);
// The actual approval signing will be done during the following incremental save operation.
doc.Save(outpath, SDFDoc::e_incremental, NULL);
```
{% endcode %}
{% endtab %}
{% tab title="Go" %}
{% code lineNumbers="true" %}
```go
doc := NewPDFDoc(docpath)
// Retrieve the unsigned approval signature field.
foundApprovalField := doc.GetField(inApprovalFieldName)
foundApprovalSignatureDigsigField := NewDigitalSignatureField(foundApprovalField)
// (OPTIONAL) Add more information to the signature dictionary.
foundApprovalSignatureDigsigField.SetLocation("Vancouver, BC")
foundApprovalSignatureDigsigField.SetReason("Document approval.")
foundApprovalSignatureDigsigField.SetContactInfo("www.apryse.com")
// (OPTIONAL) Add an appearance to the signature field.
img := ImageCreate(doc.GetSDFDoc(), inAppearanceImgPath)
foundApprovalSignatureWidget := NewSignatureWidget(foundApprovalField.GetSDFObj())
foundApprovalSignatureWidget.CreateSignatureAppearance(img)
// Prepare the signature and signature handler for signing.
foundApprovalSignatureDigsigField.SignOnNextSave(inPrivateKeyFilePath, inKeyfilePassword)
// The actual approval signing will be done during the following incremental save operation.
doc.Save(inOutpath, uint(SDFDocE_incremental))
```
{% endcode %}
{% endtab %}
{% tab title="Java" %}
{% code lineNumbers="true" %}
```java
PDFDoc doc = new PDFDoc(docpath);
// Retrieve the unsigned approval signature field.
Field found_approval_field = doc.getField(approval_field_name);
DigitalSignatureField approval_digsig_field = new DigitalSignatureField(found_approval_field);
// (OPTIONAL) Add more information to the signature dictionary.
approval_digsig_field.setLocation("Vancouver, BC");
approval_digsig_field.setReason("Document approval.");
approval_digsig_field.setContactInfo("www.apryse.com");
// (OPTIONAL) Add an appearance to the signature field.
Image img = Image.create(doc, appearance_img_path);
SignatureWidget approval_signature_widget = new SignatureWidget(found_approval_field.getSDFObj());
approval_signature_widget.createSignatureAppearance(img);
// Prepare the signature and signature handler for signing.
approval_digsig_field.signOnNextSave(private_key_file_path, keyfile_password);
// The actual approval signing will be done during the following incremental save operation.
doc.save(outpath, SDFDoc.SaveMode.INCREMENTAL, null);
```
{% endcode %}
{% endtab %}
{% tab title="JavaScript" %}
{% code lineNumbers="true" %}
```js
async function main() {
const doc = await PDFNet.PDFDoc.createFromFilePath(in_docpath);
// Retrieve the unsigned approval signature field.
const found_approval_field = await doc.getField(in_approval_field_name);
const found_approval_signature_digsig_field = await PDFNet.DigitalSignatureField.createFromField(found_approval_field);
// (OPTIONAL) Add more information to the signature dictionary.
await found_approval_signature_digsig_field.setLocation('Vancouver, BC');
await found_approval_signature_digsig_field.setReason('Document certification.');
await found_approval_signature_digsig_field.setContactInfo('www.apryse.com');
// (OPTIONAL) Add an appearance to the signature field.
const img = await PDFNet.Image.createFromFile(doc, in_appearance_img_path);
const found_approval_signature_widget = await PDFNet.SignatureWidget.createFromObj(await found_approval_field.getSDFObj());
await found_approval_signature_widget.createSignatureAppearance(img);
// Prepare the signature and signature handler for signing.
await found_approval_signature_digsig_field.signOnNextSave(in_private_key_file_path, in_keyfile_password);
// The actual approval signing will be done during the following incremental save operation.
await doc.save(in_outpath, PDFNet.SDFDoc.SaveOptions.e_incremental);
}
PDFNet.runWithCleanup(main);
```
{% endcode %}
{% endtab %}
{% tab title="Kotlin" %}
{% code lineNumbers="true" %}
```kotlin
val doc = PDFDoc(docpath)
// Retrieve the unsigned approval signature field.
val found_approval_field = doc.getField(approval_field_name)
val approval_digsig_field = DigitalSignatureField(found_approval_field)
// (OPTIONAL) Add more information to the signature dictionary.
approval_digsig_field.location = "Vancouver, BC"
approval_digsig_field.reason = "Document approval."
approval_digsig_field.contactInfo = "www.apryse.com"
// (OPTIONAL) Add an appearance to the signature field.
val img = Image.create(doc, appearance_img_path)
val approval_signature_widget = SignatureWidget(found_approval_field.sdfObj)
approval_signature_widget.createSignatureAppearance(img)
// Prepare the signature and signature handler for signing.
approval_digsig_field.signOnNextSave(private_key_file_path, keyfile_password)
// The actual approval signing will be done during the following incremental save operation.
doc.save(outpath, SDFDoc.SaveMode.INCREMENTAL, null)
```
{% endcode %}
{% endtab %}
{% tab title="Obj-C" %}
{% code lineNumbers="true" %}
```objc
PTPDFDoc* doc = [[PTPDFDoc alloc] initWithFilepath: docpath];
// Retrieve the unsigned approval signature field.
PTField* found_approval_field = [doc GetField: approval_field_name];
PTDigitalSignatureField* approval_digsig_field = [[PTDigitalSignatureField alloc] initWithIn_field: found_approval_field];
// (OPTIONAL) Add more information to the signature dictionary.
[approval_digsig_field SetLocation: @"Vancouver, BC"];
[approval_digsig_field SetReason: @"Document approval."];
[approval_digsig_field SetContactInfo: @"www.apryse.com"];
// (OPTIONAL) Add an appearance to the signature field.
PTImage* img = [PTImage CreateWithFile: [doc GetSDFDoc] filename: appearance_img_path encoder_hints: [[PTObj alloc]init]];
PTSignatureWidget* approval_signature_widget = [[PTSignatureWidget alloc] initWithD: [found_approval_field GetSDFObj]];
[approval_signature_widget CreateSignatureAppearance: img];
// Prepare the signature and signature handler for signing.
[approval_digsig_field SignOnNextSave: private_key_file_path in_password: keyfile_password];
// The actual approval signing will be done during the following incremental save operation.
[doc SaveToFile: outpath flags: e_ptincremental];
```
{% endcode %}
{% endtab %}
{% tab title="Swift" %}
{% code lineNumbers="true" %}
```swift
let doc: PTPDFDoc = PTPDFDoc(filepath: in_docpath)
// Retrieve the unsigned approval signature field.
let found_approval_field: PTField = doc.getField(in_approval_field_name)
let found_approval_signature_digsig_field: PTDigitalSignatureField = PTDigitalSignatureField(in_field: found_approval_field)
// (OPTIONAL) Add more information to the signature dictionary.
found_approval_signature_digsig_field.setLocation("Vancouver, BC")
found_approval_signature_digsig_field.setReason("Document certification.")
found_approval_signature_digsig_field.setContactInfo("www.apryse.com")
// (OPTIONAL) Add an appearance to the signature field.
let img: PTImage = PTImage.create(withFile: doc.getSDFDoc(), filename: in_appearance_img_path, encoder_hints: PTObj())
let found_approval_signature_widget: PTSignatureWidget = PTSignatureWidget(d: found_approval_field.getSDFObj())
found_approval_signature_widget.createSignatureAppearance(img)
// Prepare the signature and signature handler for signing.
found_approval_signature_digsig_field.sign(onNextSave: in_private_key_file_path, in_password: in_keyfile_password)
// The actual approval signing will be done during the following incremental save operation.
doc.save(toFile: in_outpath, flags: e_ptincremental.rawValue)
```
{% endcode %}
{% endtab %}
{% tab title="PHP" %}
{% code lineNumbers="true" %}
```php
$doc = new PDFDoc($docpath);
// Retrieve the unsigned approval signature field.
$found_approval_field = $doc->GetField($approval_field_name);
$approval_digsig_field = new DigitalSignatureField($found_approval_field);
// (OPTIONAL) Add more information to the signature dictionary.
$approval_digsig_field->SetLocation('Vancouver, BC');
$approval_digsig_field->SetReason('Document approval.');
$approval_digsig_field->SetContactInfo('www.apryse.com');
// (OPTIONAL) Add an appearance to the signature field.
$img = Image::Create($doc->GetSDFDoc(), $appearance_img_path);
$found_approval_signature_widget = new SignatureWidget($found_approval_field->GetSDFObj());
$found_approval_signature_widget->CreateSignatureAppearance($img);
// Prepare the signature and signature handler for signing.
$approval_digsig_field->SignOnNextSave($private_key_file_path, $keyfile_password);
// The actual approval signing will be done during the following incremental save operation.
$doc->Save($outpath, SDFDoc::e_incremental);
```
{% endcode %}
{% endtab %}
{% tab title="Python" %}
{% code lineNumbers="true" %}
```python
doc = PDFDoc(docpath)
# Retrieve the unsigned approval signature field.
found_approval_field = doc.GetField(approval_field_name)
approval_digsig_field = DigitalSignatureField(found_approval_field)
# (OPTIONAL) Add more information to the signature dictionary.
approval_digsig_field.SetLocation('Vancouver, BC')
approval_digsig_field.SetReason('Document approval.')
approval_digsig_field.SetContactInfo('www.apryse.com')
# (OPTIONAL) Add an appearance to the signature field.
img = Image.Create(doc.GetSDFDoc(), appearance_img_path)
found_approval_signature_widget = SignatureWidget(found_approval_field.GetSDFObj())
found_approval_signature_widget.CreateSignatureAppearance(img)
# Prepare the signature and signature handler for signing.
approval_digsig_field.SignOnNextSave(private_key_file_path, keyfile_password)
# The actual approval signing will be done during the following incremental save operation.
doc.Save(outpath, SDFDoc.e_incremental)
```
{% endcode %}
{% endtab %}
{% tab title="Ruby" %}
{% code lineNumbers="true" %}
```ruby
doc = PDFDoc.new(docpath);
# Retrieve the unsigned approval signature field.
found_approval_field = doc.GetField(approval_field_name);
approval_digsig_field = DigitalSignatureField.new(found_approval_field);
# (OPTIONAL) Add more information to the signature dictionary.
approval_digsig_field.SetLocation('Vancouver, BC');
approval_digsig_field.SetReason('Document approval.');
approval_digsig_field.SetContactInfo('www.apryse.com');
# (OPTIONAL) Add an appearance to the signature field.
img = Image.Create(doc.GetSDFDoc, appearance_img_path);
found_approval_signature_widget = SignatureWidget.new(found_approval_field.GetSDFObj());
found_approval_signature_widget.CreateSignatureAppearance(img);
# Prepare the signature and signature handler for signing.
approval_digsig_field.SignOnNextSave(private_key_file_path, keyfile_password);
# The actual approval signing will be done during the following incremental save operation.
doc.Save(outpath, SDFDoc::E_incremental);
```
{% endcode %}
{% endtab %}
{% tab title="VB" %}
{% code lineNumbers="true" %}
```vb
Using doc As PDFDoc = New PDFDoc(docpath)
' Retrieve the unsigned approval signature field.
Dim found_approval_field As Field = doc.GetField(approval_field_name)
Dim approval_digsig_field As DigitalSignatureField = New DigitalSignatureField(found_approval_field)
Dim img As Image = Image.Create(doc, appearance_img_path)
' (OPTIONAL) Add more information to the signature dictionary.
approval_digsig_field.SetLocation("Vancouver, BC")
approval_digsig_field.SetReason("Document approval.")
approval_digsig_field.SetContactInfo("www.apryse.com")
' (OPTIONAL) Add an appearance to the signature field.
Dim found_approval_signature_widget As SignatureWidget = New SignatureWidget(found_approval_field.GetSDFObj())
found_approval_signature_widget.CreateSignatureAppearance(img)
' Prepare the signature and signature handler for signing.
approval_digsig_field.SignOnNextSave(private_key_file_path, keyfile_password)
' The actual approval signing will be done during the following incremental save operation.
doc.Save(in_outpath, SDFDoc.SaveOptions.e_incremental)
End Using
```
{% endcode %}
{% endtab %}
{% endtabs %}
[Digitally sign PDF files](/core/get-started/samples/digitalsignaturestest.md) Full code sample which demonstrates using the digital signature API to digitally sign and/or certify PDF documents. Code sample is available in C++, C#, Java, Python, Go, PHP, Ruby & VB.
## About Adding An Approval Signature to a PDF Document
The Apryse SDK enables approval signatures in PDF documents using a Digital Certificate, in accordance with the latest PDF specification. By leveraging [public key infrastructure (PKI)](https://en.wikipedia.org/wiki/Public_key_infrastructure) technology, with a certificate issued by a trusted [certificate authority (CA)](https://en.wikipedia.org/wiki/Certificate_authority), a signer can use a certificate-based digital ID to guarantee the authenticity of a signature. Placement of a digital signature using a certificate can also guarantee that a document was not modified since the signature was placed, ensuring the authenticity of the document.
Image taken from Apryse WebViewer
Above is an example of a document containing a certified signature, guaranteed by a certificate generated by Apryse.com.
---
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