PDF apps?

What Samsung device do you have?

 

I was going to mention Samsung Notes, but I have no clue if that existed for your tablet or not when it came out.

On my z fold 3 with Samsung Notes, I can bring up a pdf and use my s-pen to make notes on.......I have no clue on such an old device as yours if that's the case or not.

You are not going to find many apps like that that will run on old android os....... You might be sol on this one. Get a newer device and you will find Samsung Notes is great, especially with the S-pen.

 

Try Squid - that was the app I used with my Note 10.1 (2014). And my main reason for owning a tablet is to read and annotate PDF documents, so this was my most-used app. I started using it when the tablet was still running 4.4, though I upgraded it to 5.1 as soon as that came out.

Some features require the paid version. As I believe it's entirely fair to pay people for developing apps (and far better than ad-supported crap) I had no problems with that.

I did always wonder why Samsung called that device the Note 10.1 "2014" though, since it was actually released in 2013! Reminded me of those 1990s computer magazines who always put next month's date on the front page...