A PDF form field is a type of “Widget” annotation whose purpose is to allow an end user to interactively enter data in a manner similar to filling in a paper based form.
Following is the list of available field types:
- Text
- Button
- Check Box
- Radio Button
- Choice
- Signature
Form fields within PDF are extensible; in that, their behavior can be modified with the addition of field or document level Acrobat JavaScript.
See Annotation.