PDF Form Submission and Data Formats
Under the hood, PDF form elements are a type of PDF annotation called “widget” annotations. They’re used to implement interactive form elements, such as buttons, checkboxes, combo boxes, and more.
Widgets that can hold a value — like checkboxes, combo boxes, and text fields — store their data separately in an entity called a form field. All data formats PSPDFKit supports for encoding annotations are designed to also encode the values of form fields. See our annotation data formats guide to learn more.