On-Site Invoicing & Payment: the full procedure

Deliver an itemized invoice and collect payment securely at the vehicle before leaving the job.

• Applies to: On-site technician, owner
• Frequency: Every completed job
• Scope: Covers invoicing and payment collection workflow. The invoice must reflect the authorized estimate and any re-authorized changes per the estimate/authorization SOP and repair law.

What you need

• Mobile invoicing app
• Card reader / digital payment (tap/contactless)
• Itemized line items
• Warranty terms template
• E-receipt
• Deposit reconciliation

The procedure, step by step

1. Build from the authorization — Generate the invoice from the signed estimate plus any approved change orders — no surprises.
2. Itemize everything — List parts (with numbers), labor, fluids, fees, and tax as separate line items.
3. Verify against the overage rule — Confirm the total doesn’t exceed the authorized amount beyond the allowed threshold; if it does, it should already be re-authorized.
4. Apply deposits/credits — Subtract any deposit paid at booking and any core credits.
5. Review with the customer — Walk the customer through the invoice line items before requesting payment.
6. Collect securely — Take payment via the accepted methods (tap/card/digital); never store raw card data.
7. Issue the receipt and warranty — Send the e-receipt and the written warranty terms immediately.
8. Reconcile and log — Mark the job paid, reconcile the payment, and close the job record.

Quality check before you finish

• Invoice generated from the signed authorization and approved changes only.
• Parts, labor, fluids, fees, and tax itemized.
• Total within the authorized amount / allowed overage (or already re-authorized).
• Deposits and core credits applied.
• Customer walked through line items before payment.
• Payment collected securely with no raw card data stored.
• E-receipt and warranty terms issued; job reconciled and closed.

This is a free, source-anchored standard operating procedure (SOP) you can print and hand to staff. It documents the work sequence for a Mobile Mechanic business — not safety or regulatory rulings, which defer to the cited authorities, the applicable code, and your own health-and-safety plan. Open the tool above to print it, toggle ink-saver, or (with a free ToolFluency Business account) edit it to match your own workflow.

Sources

• Bureau of Automotive Repair — "Write It Right" (bar.ca.gov)
• Federal Trade Commission (ftc.gov)
• AAA (aaa.com)