I moved your post to a better forum. From Acrobat Online to Acrobat Reader. Someone else moved your post from the Using the Community forum to the Acrobat online forum but left no reference.
Use PDF files in what way?
To Read, View and Read, PDF files on a computer, tablet (Pad) or phone no subscription and or payment is required. Just download and install Adobe Acrobat Reader on any of your devices and you can "READ" PDF files.
If you want to Create or Edit PDF files then you will need a program that cane do that. You would need Adobe Acrobat DC Pro and for that there is a subscription needed and payment for that subscription.
The Adobe Acrobat Reader program can NOT Edit PDF files.