The defendant must request the driver's safety course, either in writing or in person, on or before the defendant's court appearance date listed on the defendant's citation below their signature.
The defendant must submit a payment of $147 with the request unless, in a school zone, the amount due will be $172.
The defendant must be charged with a qualifying offense. (moving violation or involving the operation or a motor vehicle)
The defendant must enter a plea of guilty or no contest.
The defendant must have a valid TEXAS driver's license or permit or must be a member, spouse, or dependent child of a member of the U.S. military forces serving on active duty and provide proof to the court.
The defendant must have proof of financial responsibility (insurance) under the Motor Vehicle Act and provide proof to the court.
The defendant must not hold a Class A or B Commercial Drivers License (CDL).
The defendant must not have completed a DSC for dismissal of a citation in the last 12 months.
If the defendant is under the age of 17, the defendant will need to appear before the judge. (contact court for Judges hours)

Mandatory DSC is not available for certain excepted offenses like such:

Speeding 95mph or more;
Speeding 25 mph or more over the limit;
Fail to remain at a collision scene;
Duty to give information and aid;
Overtaking and passing a school bus;
Offenses committed in a construction or maintenance work zone while workers are present, except:
Inspection Offenses
Pedestrian Offenses
Safety Belt and Child Safety Seat Offenses

The City of Ennis Municipal Court does not accept personal checks. Payments must be made by cash, money order, cashiers check, or maybe paid with a credit card at the court. Payments for the DSC cannot be made online. You will receive approval and instructions in the mail shortly after the court receives your request. Do not take the course before you receive approval from the Ennis Municipal Court.
You may mail your request to the following address:
P.O. Box 220
Ennis, TX 75120