A repair invoice is different from a supply invoice in one important way: the customer usually cannot see what they bought. Something was broken, somebody went inside it, and now it works. The document has to bridge that gap, which means naming the fault as well as the work, and most free templates have no field for it at all.
The fault, then the work, then the parts
What was wrong, what was done about it, and what went in. In that order, because it is the order the customer thinks in. An invoice that opens with a part number and an hour rate reads as a bill; one that opens with the fault reads as an explanation, and explanations get queried far less often.
Labour and parts shown separately
Whether you show them separately is a market decision, and whichever you choose the invoice should match the estimate. A quoted total that arrives itemised, or an itemised quote that arrives as a total, makes every difference look like a change. Consistency prevents more disputes than transparency does.
The vehicle or the appliance identified
Registration, serial number or model, on the document. It costs one field and it makes the history searchable, which matters the second time the same unit comes back. For vehicle work it is also what makes a warranty conversation possible a year later without anybody guessing.
Keep the work order behind it
The invoice prices the job; the work order records it. Filed together against the job, they answer both of the questions a dispute produces. Records supporting income are kept for tax purposes anyway, and the Internal Revenue Service sets the general obligation out for small businesses.
Questions people ask about repair invoice template
Should a diagnostic charge appear separately?
Yes, and it should have been mentioned before the work started. A diagnostic fee discovered on an invoice is the most reliably disputed line in the trade.
What about warranty work?
Invoice it at zero with the fault and the work still named. A record that says nothing was charged is still a record of what was done.
Are free templates good enough?
As a layout, usually. Add a field for the fault and one for the unit identifier and most of them become genuinely useful.