I can think of two situations where you'll bump into this specific scenario. I'll walk you through the resolution for both of them.
First, these transactions were automatically downloaded from an online bank account you synced to your QuickBooks Self-Employed (QBSE) company. If this is the case, you can select them all, then proceed to Exclude them.
Another situation is when you manually uploaded bank transactions, and the amounts under the Debit and Credit columns were misplaced. The same thing as before, you'll need to Exclude these transactions to remove them.
For the solution, you can manually upload your bank transactions. This time, ensure that amounts are placed on the correct column, so they show up as the correct type of transaction. You can refer to this article for more information: Manually add transactions in QuickBooks Self-Employed.