> 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/web/low-level-pdf-api/add-custom.md).
# Information dictionary: adding custom data to a PDF using JavaScript
Learn how to add custom data to an existing document using the Cos/SDF low-level API to edit PDF files. Get a full code sample demonstrating the use of basic Cos/SDF API for document editing. The Apry
{% hint style="warning" %}
Make sure you have [Full API enabled in WebViewer.](/web/what-is-webviewer/full-api.md)
{% endhint %}
To add custom data to an existing document.
{% tabs %}
{% tab title="JavaScript (SDK v8.0+)" %}
{% code lineNumbers="true" %}
```js
```
{% endcode %}
[PDFNet.PDFDoc.createFromURL](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#.createFromURL__anchor) [PDFNet.PDFDoc.getSDFDoc](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#getSDFDoc__anchor) [PDFNet.PDFDoc.getTrailer](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#getTrailer__anchor) [PDFNet.Obj.putDict](https://sdk.apryse.com/api/web/Core.PDFNet.Obj.html#putDict__anchor) [PDFNet.Obj.putString](https://sdk.apryse.com/api/web/Core.PDFNet.Obj.html#putString__anchor) [PDFNet.Obj.putNumber](https://sdk.apryse.com/api/web/Core.PDFNet.Obj.html#putNumber__anchor) [Core.setWorkerPath](https://sdk.apryse.com/api/web/Core.html#.setWorkerPath__anchor)
{% endtab %}
{% tab title="JavaScript (SDK v6.0+)" %}
{% code lineNumbers="true" %}
```js
```
{% endcode %}
[PDFNet.PDFDoc.createFromURL](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#.createFromURL__anchor) [PDFNet.PDFDoc.getSDFDoc](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#getSDFDoc__anchor) [PDFNet.PDFDoc.getTrailer](https://sdk.apryse.com/api/web/Core.PDFNet.PDFDoc.html#getTrailer__anchor) [PDFNet.Obj.putDict](https://sdk.apryse.com/api/web/Core.PDFNet.Obj.html#putDict__anchor) [PDFNet.Obj.putString](https://sdk.apryse.com/api/web/Core.PDFNet.Obj.html#putString__anchor) [PDFNet.Obj.putNumber](https://sdk.apryse.com/api/web/Core.PDFNet.Obj.html#putNumber__anchor) [CoreControls.setWorkerPath](https://sdk.apryse.com/api/web/Core.html#.setWorkerPath__anchor)
{% endtab %}
{% endtabs %}
[Cos/SDF low-level API to edit PDF files](/web/get-started/samples.md#sdf) Full code sample which illustrates how to use basic Cos/SDF API to edit an existing document.
---
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