I don't have an option either via the app store or system preferences to upgrade my mac book pro 2012. The app store shows 4 updates but it is just blank and nothing ever shows up. Is there another way to upgrade to OS? It is running High Sierra 10.13.4
Thanks in advance
A 2012 MacBook Pro should be able to be upgraded to Catalina 10.15.7. See instructions in: How to get old versions of macOS - Apple Support (if not what you've already tried)
A 2012 MacBook Pro should be able to be upgraded to Catalina 10.15.7. See instructions in: How to get old versions of macOS - Apple Support (if not what you've already tried)
Mac Book Pro 2012
