Flattening a PDF means merging all its interactive layers — form fields, annotations, and markup — into a single, static layer. The result looks identical but the fields are no longer editable. Here's when and how to do it.
What Does "Flattening" Actually Do?
An unflattened PDF with form fields is essentially a template — the fields can be cleared, modified, or re-filled. When you flatten it:
- Form fields become permanent text that can't be changed
- Annotations and highlights become part of the base page
- Signatures are locked into the document
- File size often decreases
The document looks the same, but it's now a static snapshot.
When Should You Flatten a PDF?
- Before archiving — prevent future editing of completed forms
- Before printing — some printers mishandle interactive form fields
- Before emailing signed documents — ensures the signature can't be removed or altered
- Before uploading to portals — some systems don't render form fields correctly
How to Flatten a PDF
Method 1: Print to PDF
The simplest method works on any platform:
- Open the PDF in your browser or PDF reader
- Press Ctrl+P (Cmd+P on Mac) to print
- Select Save as PDF or Microsoft Print to PDF as the printer
- Save the output
The resulting PDF has everything flattened into the page — no editable fields remain.
Method 2: Use Adobe Acrobat Pro
If you have Acrobat Pro:
- Open the PDF
- Go to Tools → Print Production → Flattener Preview
- Apply the flattener with your preferred settings
Acrobat gives you fine-grained control over what gets flattened.
Method 3: Export from a PDF Editor
After filling out a form in Docento.app, the exported PDF is effectively flattened — your text entries and signatures are rendered directly onto the page as part of the document. See how to fill out a PDF form for the full workflow.
How to Check if a PDF Is Flattened
Open the PDF and try clicking on the text areas or form fields. If nothing is selectable or editable, the PDF is flattened.
Can You Unflatten a PDF?
No — once flattened, the process is irreversible. Always keep a copy of the original interactive PDF before flattening if you might need to edit it again later.