Hello there, @natashancaiden.
You can link Square with QuickBooks Online (QBO), however, there's no Square sync functionality with QuickBooks Self-Employed (QBSE). Also, we aren't able to connect Venmo to QBSE.
The good news is, you can prepare an Excel CSV file and import your Square or Venmo transactions to QuickBooks. For your reference, read these articles:
Get back to me if you have any other questions. I'm a few clicks away to help. Happy weekend!