Sales receipts
A sale paid on the spot: one document that records the revenue and the money in the same step, with no receivable.
Sales → Sales Receipts → New.
An invoice records a sale and waits to be paid; a sales receipt records a sale that has already been paid. The form is the invoice form plus Payment method and Deposit to, and saving it posts revenue (and tax) and the deposit together — nothing touches Accounts Receivable and there is no balance to chase.
Deposit to is the bank account or Undeposited Funds if the money is banked later as part of a batch. Numbering is its own sequence (SR-1001 by default; see Document numbering). Tax, discounts, items and customer behave exactly as on an invoice — see Invoices and estimates.