As I am coming from QuickBooks I was using “Sales Receipt” for instant payments. I am not sure whether this is something unique to QuickBooks only.
Here is what I found from QuickBooks help
An invoice is used when your customer agrees to pay you later. You can set up terms to indicate how long the customer has to pay. If they don’t pay within the specified time limit, their invoice is overdue.
A sales receipt is used when your customer pays you on the spot for goods or services.