Hi Akki_24, I ended up figuring this out and it had to do with the version of pdf that I was generating and the font-type being used within the form fields. Hopefully, this is helpful to anyone generating forms in a pdf using libraries like fpdf + fpdm (written in php). I have since moved everything over to use the mpdf library (still php) and don't have the same problems now. I created a pdf template that had form fields in it using a free program called Scribus. I know, I know... I am in an Adobe forum suggesting that I used another product to create a pdf! However, I do own a copy of Acrobat DC and use it for everything else... For just this one application, I needed something else because the version of pdf that Adobe DC created (I did try to use it first) wasn't readable by the fpdf + fpdm libraries mentioned above (I had spent way too long already trying to tweak settings in Adobe DC, couldn't get it figured out and had already past a deadline to get my forms posted on our site). Scribus generated pdfs only worked with my scripts if I saved them to version 1.3 (equivalent to Adobe legacy ver. 4 or 5, so the forms weren't pretty and didn't need to be). What I didn't realize however, is that when you go back that far (I remember those days... Ugh... I'm old...), you have to specify that a TrueType font (Helvetica for example) be used within the form fields when completing them in Adobe Reader. Not knowing this, I was trying to use Montserrat. I am assuming that if Adobe Reader detects that the pdf is saved as an older version, it applies the legacy code that governed a pdf back then to be able to interpret and display them properly. The reason that the browser pdf readers let a user fill in the field (from what I'm assuming) is because they must not revert back in time to when people knew who Austin Powers was, to follow whatever font limitations those versions applied. I could understand that Adobe Reader versions dating back that far specified which fonts (TrueType) that could be used to keep the document formatted nicely whereas, neither Chrome or Firefox even existed back in those days (unlike Adobe, they will never know what life was like when Tupac was around). ... View more