Services
Service billing software
An estimate, then a proforma, then the invoice. No stock. Sales tax on the fee.

Estimate
The quote is a document. A sale order can follow it.
Invoice
Retainer, project, and visit are the categories. The fee prints with tax.
No stock
This preset turns stock, POS, barcode, and warehouses off.
Sales tax
The tax sits on the invoice. Payment follows the bill.