adding driver commission to wallet

hi, how are you

im trying to figure out a way to add drivers commission to his wallet(woo-wallet/terawallet)

but first i need know what is the $var for commission amount from this plugin then do a bit of RESTAPI calling to add the amount to drivers wallet.

i need to do this on delivery complete screen
witch file and what line is proper to do it to be part of delivery complete process. (im asking this because dont want to brick to proccess)

things needed
1.how to call commission var
2.what file is the delivery complete page process

hope i was explained my train of thought.
thank you for your time.