Can I update Adobe?

There is one that 'claims to be free' while that may not fully be the case.

Some mac users had no great experiences from later 'free' DC versions.

[While the professional level Adobe Acrobat is retail-priced* from maker.]

*https://acrobat.adobe.com/us/en/acrobat/free-trial-download.html

• Adobe Acrobat Reader DC Install (free) for all versions | adobe

https://get.adobe.com/reader/

About:

Adobe Acrobat Reader "DC" software is the free global standard for reliably

viewing, printing, and commenting on PDF documents

A fairly good PDF reader with some edit capability is Apple's Preview.

LibreOffice https://www.libreoffice.org/download/download/

has a component in their free office suite to handle PDF + other files.

Go to the Adobe website and see if you can download a version of Acrobat that will run on your macs OS.

httpshttps://www.tomsguide.com/best-picks/best-pdf-editors

https://www.tomsguide.com/best-picks/best-pdf-editors

A list of options: https://alternativeto.net/software/adobe-acrobat/?platform=mac