Interactive and flat forms work differently
An interactive PDF has built-in fields that a viewer can select. A flat form is just page content, sometimes a scan. PDFOnHand can fill supported interactive fields; for flat forms, the text and annotation tools let you place answers visually on top of the page.
Start with a short test
Some forms use advanced scripts, special formatting or field types that a browser editor may not fully support. Fill one or two fields and download a test copy before completing a long form. If an organization requires a particular application, use that application.
Finish with the right signature
You can place a drawn, typed or image signature using Sign PDF. That is a visual signature, without a certificate, identity verification or audit trail. Check the recipient’s requirements before relying on it for an official submission.