How to lock a pdf to permit only form filling and no other changes
- Step 1Upload the fillable PDF form — Drop the form into the permission setter.
- Step 2Enable form-fill permission only — Turn on Fill-In Forms and disable all other change permissions.
- Step 3Set the owner password — Protect the permission settings.
- Step 4Distribute the locked form — Recipients can complete the form but cannot alter its structure.
Frequently asked questions
Can recipients save the completed form?+
Form-fill permission allows field entry. Saving depends on the viewer — Adobe Reader can save completed forms if the document has Reader Extensions enabled.
Will they be able to add annotations or comments?+
No — if annotation permission is disabled, recipients cannot add comments or sticky notes.
Should I flatten the form after recipients return it?+
Yes — flatten returned forms before archiving to lock the submitted data as static content.
Privacy first
All PDF processing runs locally in your browser using PDF-lib and pdf.js. No file is ever uploaded — only metadata counters are saved for signed-in dashboard stats.