How to upgrade my mid 2012 MacBook Pro to Big Sur?

Hi 2012 MacBooks can't upgrade to macOS Big Sur but can upgrade to macOS Cantila.

To do this search for "MacOS in the Mac app store" on your browser. If you open the link on the apple website, it will redirect you onto the App Store where you can download it. Please rate my answer. Thank you. I hope that helps you.

Explore the Apple Trade-In  Process where the Value of the exiting device could be used against the cost of a new Apple Computer, iPhone or iPad  

Or Shop Refurbished Apple computers at an Apple Reduced Cost

Have used both previously and have been satisfied each time.