How-To2026-03-222 min read
How to Flatten a PDF — Lock Form Fields Permanently
What Does Flattening Do?
Flattening a PDF converts interactive elements into static page content:
Form fields → permanent text
Annotations → embedded in page
Comments → fixed in place
After flattening, nobody can edit the form data.
When to Flatten
Before archiving completed forms
Before sharing filled-in documents
To ensure consistent printing
To reduce file size (sometimes)
How to Flatten
Go to Flatten PDF
Upload your PDF
Click Process & Download
The output has all interactive elements locked
Warning
Flattening is permanent. Always keep a copy of the original editable PDF.
Related Tools
Protect PDF — password protection instead of flattening
Edit PDF — add text before flattening