Form data can be saved and loaded the same way as annotations through XFDF data.

Please see import/export annotations to learn more.

All of the form field data (field values and widget appearances) is included inside XFDF, for example when calling annotManager.exportAnnotations.

A short introduction to XFDF file format
An introduction to XFDF file format

Importing and exporting annotations
To import and export annotation and forms data through XFDF data.