Depends a bit on what model year it is. If it is a “Retina” machine, you won’t be able to upgrade the components in the machine except for the drive with some adapters. If you have a machine from 2012 or before which ich chunkier and has a DVD drive, you will be able to change the memory (RAM) and the hard disk. Software wise the machine is no longer supported by the newest OS, but with so called patchers you can run modern macOS versions on your laptop, as the other comment mentioned.
Performance wise you should see an increase of up to 15% with most applications. The M2 runs hotter than the M1, so for sustained load tasks, it may end up being a bit slower. However for the reasons you bought this machine it is still worth the upgrade. You get MagSafe and a bigger, better screen, better speakers and nicer design plus an increase in performance for day to day things. Depening on your use case the loss of the touchbar may also be a positive. If I’m guessing right your work will involve a lot of opening and closing of documents and the M2 Air will be able to handle it perfectly fine I think.