Fill out a form file
Apple iOS (iPhone & iPad)
Simpler ways to do this all appear to require buying a third-party app or uploading your PDF to a potentially less trustworthy platform. So, this seemingly over-complicated method is the simplest I've yet found. Please tell me if you know an easier one!
(If you're a programmer, please help make flattening a PDF a standard export option... it boggles my mind that it's not.)
If the file is a PDF…
Save it to the Files app.
If the file is not already a PDF…
…such as a Word doc, first convert it to PDF.
Save the file to your Google Drive app.
In Google Drive app, beside the file, select more_horiz › Print › upload › Save to Files › Save.
Fill out the PDF form
Open the Files app.
Find and open the PDF.
Select AutoFill Form, either from the pop-up at the top, or from the dots & pencil icon in the lower right.
Note: These options may take a moment to appear.
Now you should see blue fields where you can add text.
Tip: If any blue fields are missing, or if the AutoFill option didn’t work, you can add and format text wherever you like.
Select the pen tip icon › add › Add Text › Aa (to format). Select then drag the text box anywhere.
Sign the form
Select the pen tip icon › add › Add Signature, then either add a signature or select one you already made.
Select and drag to move or resize your signature.
Flatten the PDF
When you’re done filling out the form, it’s important to “flatten” it, so that other people cannot easily change your answers.
Upload your completed form to your Google Drive app.
In the Safari app, sign into drive.google.com open_in_new.
Note: This must be done from Safari in order to work. Wild, I know.
On the left side of the address bar, select menu › more_horiz , then turn on Request Desktop Website.
Select Done.
Note: Your Drive should now look as it does on a computer. If it doesn’t, refreshing the page may help.
Double-tap your PDF to open it.
Select print, which will open the PDF in a new window.
In the bottom Safari menu, select upload › Print › upload › Save to Files › Save.