> 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/xamarin/forms/form-fields.md). # PDF Form Fill Library in Xamarin Learn how to import, export, and fill form data in PDFs with this comprehensive guide. Create new form fields, merge data, and flatten forms effortlessly. The Apryse Xamarin SDK streamlines secure, se An interactive form (sometimes referred to as an *AcroForm*) is a collection of fields (such as text boxes, checkboxes, radio buttons, drop-down lists, and pushbuttons) for gathering information interactively from the user. A PDF document may contain any number of Fields appearing on any combination of pages. All these fields make up a single, global interactive form spanning the entire document. While PDF forms are similar to HTML forms, there are some important differences: * Unlike HTML pages, a PDF document has a single, global interactive form spanning the entire document. * In PDF documents, the field and value appearance can be completely customized. Although field appearances give incredible customization power to PDF forms, developers need to learn to work with forms where field's value and appearance are two different entities. * The PDF format supports combo boxes with text editing. * In the PDF format, it's possible to associate fields with different kinds of Actions (or Action chains). Apryse SDK fully supports reading, writing, and editing PDF forms and provides utility methods to make working with forms simple and efficient. Using the Apryse SDK forms API, arbitrary subsets of form fields can be imported or exported from the document, new forms can be created from scratch, and the appearance of existing forms can be modified. Forms Data Format (FDF) and XML Forms Data Format (XFDF) contain a list of Form Fields with their associated values. These formats can be used to import and export form data to and from PDF Form Fields. Apryse SDK benefits include: * Fill PDF Forms * Read PDF form field values * PDF form field flattening * Support for all form field properties and appearances * Support for encrypted PDF forms * Support for FDF (Forms Data Format) * Import FDF to PDF * Export FDF from PDF * Forms templating * Form field name management * Create new form fields * Support for JavaScript calculation in forms ## Get started [Import form data into a PDF](/xamarin/forms/import-data.md) To import XFDF into FDF, then merge data from FDF into PDF. [Export form data from a PDF](/xamarin/forms/export-data.md) To extract data from PDF to FDF, then export FDF as XFDF. [Create new form fields and widget annotations](/xamarin/forms/new-fields.md) To create new form fields and widget annotations within a new document. [Fill form fields](/xamarin/forms/fill-fields.md) To modify values for existing form fields. [Form flattening](/xamarin/forms/flatten.md) To flatten form fields in a PDF document. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.apryse.com/xamarin/forms/form-fields.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.