@dplagens2
"Can I manually add a transaction?"
Yes, definitely!
To manually add a transaction in QBO:
Select "+ New" from the left Dashboard.
You can add any customer and vendor related transactions from here.
If it's a bank-related transaction, you can directly add to a bank register.
(Left Dashboard > Accounting > Chart of Accounts > Select Bank Account > Click View Register > Select Add Expense and so on.