You can do it online through the DMV website, you can log in as guest if you don't already have a DMV account:
https://www.ncsbe.gov/registering/how-register/complete-your-registration-online-through-dmv
Voting for the GOP in NC is no different than voting DEM, today proved that. I contacted both my senators and congressman a few days ago, not a one even bothered responding. They are no longer worthy of my support.
In some states you can't participate in any primary election if unaffiliated. How will you primary out the RINOs?