Placards
A disabled parking placard in Hays County starts with Form VTR-214
The blue hangtag placards and disabled-person license plates are handled at the Hays County Tax Assessor-Collector's motor-vehicle counter at 712 S. Stagecoach Trail in San Marcos, the same place you'd register a car. The application is TxDMV Form VTR-214, and the middle section has to be filled out and signed by a licensed doctor, physician assistant, advanced practice nurse, or other qualifying health-care provider certifying the disability. That signature is the part that holds people up, so get it before you make the trip.
There are two kinds. A permanent placard is free, issued for conditions that won't improve, and renews on a set cycle. A temporary placard, for a recovery from surgery or an injury, say, carries a small fee and an expiration tied to how long your provider expects the disability to last. You can hold one placard plus disabled-person plates, and the placard hangs from the mirror only while the car is parked, never while driving.
Download Form VTR-214 ahead of time from txdmv.gov so the counter visit is quick. If a placard is lost or stolen, the same office handles the replacement.
Source to confirm: TxDMV – Disabled Parking, Placards & Plates