A home service contract may cover a unit that sits in your house, and the repair may happen in your house or at a shop that takes the unit in. Those are two different jobs, and the contract may treat them differently. Before you book, decide where the repair will happen, then read what the contract says about that place. This piece has not read any particular contract, so it describes what to look for in general.
What the location changes
A technician who comes to the home works on the unit where it stands. A drop-off repair moves the unit, so the paperwork should show who moves it, who arranges the move, and who is responsible if it is damaged on the way. Check whether the contract names an in-home visit, a shop visit, or both. If it names only one, the other may not be available under that contract, and a shop you pick on your own may not be an approved repairer.
Questions to ask before you book
Ask whether the approved repairer comes to the home or only takes units in. Ask who arranges transport and whether any charge applies for it. Ask how long the unit may be out of service, whether a substitute unit is provided, and what wording the contract uses to say so. Ask what happens if the repair cannot be finished at the location you chose, and whether the contract lets the job move to the other location without opening a new claim.
Where doing it yourself fits
Some contracts state that owner repair can affect cover. Read that clause before you open a panel or disconnect any part, and keep a plain record of who touched the unit and when. This piece does not say whether any task is safe for you to do. Where a task involves gas, high voltage, or refrigerant, the rules for licensed trades may apply, so check the state's rules first. The state pages on this site name the statute or program each state uses and say whether the state publishes a roster, for example the Georgia page.