How do i mark invoices as paid when not sent through quickbooks?

Hey there, @nickubik-googlem.

You can mark your invoice as paid even though you haven't sent them through QuickBooks. Let me show you how:

1. Go to Sales and select Invoices.
2. Look for the transaction, then click Receive payment.
3. From the Payment method drop-down list, choose the payment method.
4. Select the account you put the payment into from the Deposit to drop-down menu.
5. In the Outstanding Transactions section, select the checkbox for the invoice your recording payment for.
6. When you're done, choose Save and close.

This should now mark your invoice as paid. 

Additionally, there are several financial reports you can run to track your sales income in QuickBooks. They will show you helpful insights on the things you buy and sell, and the status of your inventory.

Don't hesitate to tag my name in the comment section below if you have other concerns or questions. I'm always ready to help.