Can customers order from a tablet I leave on the table instead of scanning a code?

There is no tablet on the table mode, and you do not need one. A restaurant tablet ordering system means buying, charging and cleaning a tablet per table, and a QR card does the same job on the guest's own phone. If you want staff to take the order at the table, a waiter's phone paired under Settings → The POS opens on the floor plan and sends the round to the kitchen. Guests who prefer not to scan can order through the waiter. The Tables, tabs and the kitchen screen tab in the docs covers waiter phones.