Good morning,
I am not completely sure what you are asking. :-)
Depending upon the legal form of your business, Company, Partnership, Limited Liability Partnership, Sole Trader etc the exact requirements change and an Internet search may help.
If you are after a high quality letter head one that looks like it is printed by the same laser printer as the rest of the document doesn't cut it, but for a typical garage that doesn't seem relevant.
For example: If you are self employed and have a trading name you must also include your own name as well as the trading name.
Bye
Ian