Before any repair is covered, the administrator has to tie the contract to the right vehicle. The link runs through the vehicle identification number. If that number is wrong on one page, the claim may be handled as if it belongs to another car, or it may stall while someone checks the record. A few minutes of matching now can save a difficult conversation later.
Find the number on the car
Read the full run of characters from the dashboard plate visible through the windshield and from the label on the driver's door frame. Those two places should agree with each other. If they do not, stop and ask the seller to explain before you sign anything.
Compare it to every document
Check the number on the contract, the registration, the title, and any odometer disclosure you received at the sale. Compare them character by character, not by eye. Confirm that the make, model, and model year on the contract match the car as well.
Ask how the administrator records it
Ask the administrator which vehicle record it will open for your car and how it will confirm that record to you. Ask whether a correction form exists and how long a correction takes to process. Write down the names of the people you spoke with and the date of each call.
Keep the proof
Save a copy of each document showing the number, and keep a note of any confirmation you receive. If the number is later questioned, the matching record is what settles the matter. The company comparison table on this site lists the published terms for each provider, which can help you see how each one describes its enrollment steps before you commit.