Macbook Air - Cantina last Update

How far you can update a Mac will depend on its model, and hardware model year.

If this is a MacBook Air (13-inch, Mid 2012), it cannot update past Catalina.

If this is a MacBook Air (13-inch, Mid 2013), it cannot update past Big Sur.

How to download and install macOS - Apple Support

Neither is among the "most recent three" supported by companies such as Microsoft and Adobe. I believe both are recent enough to run current versions of

• The Firefox Web browser
• The LibreOffice office suite
• The commercial Affinity V2 applications (Photo, Designer, Publisher)

which might let you get a little more useful life out of that old MacBook Air. Those MacBook Airs came with either 4 GB or 8 GB of RAM (non-expandable); hopefully you have an 8 GB model.

If you want to run the current version of macOS, Sequoia, you will need a much newer Mac – preferably one with an Apple Silicon chip. Apple is already up to M4-series chips in MacBook Pros and M3-series chips in MacBook Airs – and there are no Intel-based Macs anywhere in Apple's current new product line.

macOS Sequoia is compatible with these computers - Apple Support

I assume you mean Catalina.

If that’s as far as it will go, then that’s as far as it will go.

A mid 2013 model can upgrade to Big Sur, macOS 11.

If it’s a 2012 model that you bought in 2013, Catalina is the end of the line.

Either way, it’s at least 11 years old. It had a good life. it’s time for a new machine.