I'm trying to erase my Macbook Air
I'm having a hard time finding the erase all information when I go to Preferences on my Macbook Air
MacBook Air 13″, macOS 11.6
The option in Preferences is only available on recent Macs that have the T2 chip -- see: Mac models with the Apple T2 Security Chip - Apple Support or on Macs that have Apple silicon (M1, M2) rather than an Intel cpu.
For older Macs, skip step 2 in What to do before you sell, give away, or trade in your Mac - Apple Support and use the remaining steps instead.