1) In QB online, after doing and sending an estimate, and then after editing the estimate, there should be a "Review and send" button in the estimate. There is a "Review and send" button in the original estimate, but not on a revised estimate. There is a way to send a revised estimate, but it is cumbersome; see Case # 15130491567.

2)There should be a way to copy an invoice into a new estimate. Now an estimate can be copied to a new estimate, and an estimate can be copied into a new invoice, and an invoice can be copied into a new invoice, but an invoice cannot be copied into a new estimate.