Keep your Older Computers for Longer

It's pretty easy to do as others have said. I would recommend plugging it into Ethernet during installation if you can and decide to install Linux. I say this bc as another user mentioned, you likely have a Broadcom wifi/bt chip and the drivers are "non-free". You don't have to pay for them or anything, but they can't include them with the installation image. If you're hard wired to internet, most will detect the hardware and ask if you want to install those drivers, though.

It can be a bit technical, but there are a ton of videos out there describing how to do it.

With user-focused Linux distributions like Mint Linux, it is not hard. The only thing that is slightly scary: MacBooks show 1 minute black screen on boot. Don't worry. That's the usual way Apple tries to scare users from using non-Apple stuff.

Oh, and you should check if you have a Broadcom WiFi chipset. Broadcom does not share hardware infos and I'd recommend that you get a USB WiFi stick. God, I hate this company so much.

This has a decent comparison of the different Linux distros.

https://www.macworld.com/article/672021/how-to-install-set-up-linux-on-a-mac.html