Send an Invoice
Sending an invoice (the Send Invoice button on the invoice) moves it from draft to sent and gives the customer a private link to open it. Use it when the lines are right and you are ready to ask for payment.
At the moment of sending, the tax on the invoice is worked out again from its lines, discount, address and exemption as they stand then, so the issued invoice carries the figures it had when it went out. A deposit invoice is also checked against its estimate before it can be sent, and an invoice that is not a draft cannot be sent again as a new issue.
Sending comes after creating the invoice and before collecting payment. Once an invoice is sent, you can create a payment link for it, charge a card, or record a payment that was received another way.