how do I update my operating system on MacPro 2015
how do I update my operating system on MacPro 2015
MacBook Pro 13″, OS X 10.10
Note that the following is for a MacBook Pro (at the bottom of your post), not a Mac Pro.
An early 2015 through 2016 MacBook Pro can be upgraded to the latest version of Monterey macOS 12. See: How to download macOS - Apple Support
Also note that if you upgrade to Catalina, Big Sur or Monterey you will also need to update any non-Apple 32-bit apps if you have any. See: https://www.macworld.com/article/232735/how-to-check-if-mac-software-is-32-or-64-bit.html