Can a customer leave a tip?

On the pay page a customer can add a tip when you allow it. A tip is never pre-selected and "No tip" is always one tap; the suggestions are flat dollar amounts scaled to the size of the bill, not percentages, because nobody tips 20% on a furnace install. You set the largest invoice a tip may be offered on, or turn tips off. Until you set it, the prompt follows your trade: on where tipping is customary (cleaning, moving, hauling, grooming, salons and the like) and off where it is not (roofing, fencing, concrete, HVAC and plumbing installs). The tip arrives with the payment; the invoice shows no separate tip line. It stays separate from the invoice balance and is recorded as tips income. The cash received includes that tip, less any processing fee.