New resident
Just Moved to Amarillo? Get Your Car on Texas Plates
Move to Potter County from another state and you have 30 days to register your vehicle in Texas. The place to do it is the county tax office at 900 S. Polk, Suite 106, on the ground floor of the Santa Fe Building in downtown Amarillo. County tax assessor-collector offices handle first-time registration for people relocating here.
Bring proof you own the car, which usually means the title or registration from your old state, plus a current Texas liability insurance card. First-time registrants also fill out a Form 130-U. Here's a break the big-city folks don't get: Potter County isn't one of Texas's emissions-inspection counties (those are clustered around Dallas-Fort Worth, Houston, Austin, and El Paso), so an ordinary personal vehicle skips the tailpipe test entirely. Commercial trucks still run on their own inspection rules.
If you can, knock it out early in the month. The window in the Santa Fe Building keeps regular weekday hours, and getting in before your 30 days runs down means you're not paying a late fee on top of the registration.
Source to confirm: TxDMV — New to Texas