ipad air model 1474 with ios 12.5.7 how to go higher ios

An unit on 12.5.7 isn't capable of 13 or above; for an iPad Air, it's a first generation model.

(250422)

Sorry, not possible. The A1474 model number corresponds to a first generation iPad Air from 2014. It lacks the hardware, RAM and CPU to run anything newer than iOS 12.5.7.

If you need a more modern iOS version, then you'll need a newer iPad that can run it.