If you are a resident of Texas you should normally be able to register and insure a car you bought in Oklahoma in TX.
The Texas Department of Transportation (DOT) handles the title and registration of vehicles in the state of Texas. If you have been a resident of TX and went up to Oklahoma to purchase the vehicle and bring it back to Texas then you should contact your local DOT office to see how to switch the registration over to TX from OK.
If you are a new resident to TX and just moved there with your vehicle that was previously registered in Oklahoma then you are required by Texas state law to get a Texas vehicle inspection, vehicle title/registration and driver license. You must follow these steps within 30 days of moving to Texas to operate your vehicle legally.
The registration process in Texas is fairly simple. You first must have the car pass a vehicle inspection then take the inspection certification and proof of insurance to your TX county tax office.
Here you will need to provide the vehicle's odometer reading, if the vehicle is less than 10 years old. You then must present an original out of state title. If the title is unavailable for some reason then TXDOT notes you can bring your out of state registration document and proof of sales tax payment.
You will need to submit a vehicle title/registration form (you can print this off of the TXDOT website) and pay a registration fee, title application fee and if you are a new resident then a new resident tax of $90.
For a Texas auto insurance quote, click here.