What does it mean to flatten a PDF, and when should you?

Before and after

Before flattening, someone can click into a field and change your answer, or move a signature image. After flattening, the answer is printed on the page like ink on paper.

When to flatten

• After filling an application form, before submitting it.
• When a portal rejects your file as 'fillable' or 'contains form fields'.
• When comments display differently in different viewers.
• After signing, so the signature cannot be moved.

How to flatten

• Fill the form with PDF Form Filler and sign with Sign PDF if needed.
• Open Flatten PDF and add the completed file.
• Download the flattened copy and keep the original in case you need to edit answers.

What flattening is not

It is not security. Anyone can still read the file. If it is confidential, add a password with Protect PDF.