Parking placards
Disabled parking placards are a Smith County Tax Office service
A disabled parking placard comes out of the same county tax office that renews your registration. It's one of the standard services those offices handle for the state, sitting right alongside titles and tags.
The form is VTR-214, the application for a disabled parking placard or license plate, and you can't finish it on your own. A doctor or other health care provider has to complete the disability statement section before the application is any good to the tax office.
Smith County runs its main tax office in Tyler, with substations out in Noonday, Lindale, and Troup. Not every service is offered at every one of them, so a placard you could pick up in Tyler might not be handled at the Troup window. Call the substation before you make the drive.
Source to confirm: TxDMV - Smith County Tax Office