How to flatten a PDF form so the answers cannot change
In Fill in a form, tick Seal the answers and press Fill it in. The answers are flattened into the page: they look the same, but they are no longer boxes anyone can type into.
Fill in a formFree. Nothing is uploaded.
How to do it
- Open Fill in a form and add the filled form.
- Check the answers in the list, and change any that need it.
- Tick Seal the answers.
- Press Fill it in.
- Save the sealed copy and send that one; keep the fillable original for corrections.
What flattening means
A fillable PDF keeps each answer in a field that sits on top of the page, separate from what is printed. Flattening, which this site calls sealing, writes each answer into the page itself and removes the fields. The sealed form looks just as it did, but there is nothing left to click or type into, and the answers travel as part of the page wherever the file goes.
Why offices and portals ask for it
Answers in fields can be changed by anyone who opens the file, which is the point while a form is being filled, and a problem once it is final. Fields can also behave differently from one program to another: some forms’ fields do not print, some simple viewers show them empty, and when two copies of the same form are joined into one file, fields with the same name can end up showing the same answer. A sealed form avoids all of that: what you see is what everyone sees.
Sealing a form filled somewhere else
You can seal a form that was filled in another app. Add it here, and the answers already in its fields show in the list. Tick Seal the answers and press Fill it in without changing anything, and the answers as they stand are written into the page.
If the tool says the PDF has no fields, there is nothing left to flatten: either it was sealed already, or it was only ever a printed page.
Before you seal
Sealing cannot be undone in the sealed copy, so keep the fillable one: the file you picked is never changed, and a corrected version is a minute’s work from it. Check every answer in the list first, especially dates and numbers. If you will fill the same form again, tick Also save my answers as a file in the same run.
Answers in English letters stay real text after sealing, so they can still be searched and copied. An answer in Malayalam, Hindi or another script the form’s font cannot draw becomes a picture of its words, which reads correctly everywhere but cannot be searched.
Sealed is not locked
Sealing stops the answers being edited as form answers. It does not stop a determined person editing the page, any more than a printed form stops someone with a pen. To stop the file being opened at all, lock it with Add a password. To show who signed and that nothing changed since, add a digital signature last, after sealing.
A worked example
An insurance claim form arrives as a fillable PDF, and the claims portal wants the completed form and the hospital bills as one PDF. Kavya fills it in with Fill in a form, leaving Seal the answers off, and checks the result. When it is right, she adds that filled copy, ticks Seal the answers and presses Fill it in. She taps Then, chooses Merge, adds the bills after the form and presses Merge into one file. The portal gets one file whose answers cannot be changed or lost on the way.
Questions people ask
Is flattening the same as Seal the answers?
Yes. Seal the answers flattens the form: every answer becomes part of the page, and the fields are removed.
Can I unflatten a form?
No. Once sealed, the answers are printed on the page. Go back to your fillable original, which is never changed.
Is my form uploaded to be flattened?
No. It is sealed in your browser, on your device, and nothing you typed is sent anywhere.
Does a locked form stay locked?
Yes. Type its password when asked; the sealed copy keeps the same password.
Can I flatten a form on my phone?
Yes. Tick the box and press the button, just as on a computer. See fill and sign a form on your phone.
Your file stays on your device. Foolscap does the work inside your browser, so nothing is uploaded and there is nothing for anyone to keep. How you can check