We "added" some of our deposits without matching them to a Sales Receipt. Can we match those transactions to a Sales Receipt without "undoing" the transaction?

Hey finance80. In order to match them correctly in QuickBooks Online, you will need to undo the transactions. Fortunately there's a way to Batch Undo from the banking tab that can make this rather painless. Follow the steps below to fix the transactions.

How to Batch Undo Transactions

1. Select Banking on the left.
2. Now, make sure the correct bank is selected and then select the Reviewed tab 
3. From this screen, select the checkbox next to all the transactions in question. 
4. Now press Undo in the top left corner. 

If there's anything else I could answer for you, let me know I'm here to help.