What OS can I update my 2012 iMac to? Currently has OX 10.95 Maverick?…?

Note that when you upgrade to Catalina, many older apps will stop working.

See: 32-bit app compatibility with macOS High Sierra 10.13.4 and later - Apple Support

Some developers have Catalina-compatible update available, Other you require you purchase a newer version. Others have abandoned older 32-bit apps completely.

This tool will check your current apps for any not compatible with Catalina:

https://www.stclairsoft.com/Go64/index.html

Run it BEFORE you upgrade.

If you find that any of your critical-need apps cannot be updated to run on Catalina 10.,15, then only upgrade to Mojave 10.14.

Also not that you must use Safari for downloading and installing the Apple upgrade files that dialabrain linked.

It can be upgraded up to Catalina. You should probably upgrade to El Capitan first.

See: How to get old versions of macOS - Apple Support

Allan Jones wrote:

Also not that you must use Safari for downloading and installing the Apple upgrade files that dialabrain linked.

FWIW, since they changed the Big Sur through High Sierra links to start with macappstores instead of https, other browsers work as well.

You're welcome.

Good to know. Thanks!

You're welcome.