When a payment is received for an invoice that was sent to a customer, how do i match that payment to its invoice and still categorise what it was received for?

Hello WHAH, Thanks for your query about matching and categorising payments.  To match transactions, you can follow these steps: Find a downloaded transaction with the Match option in the Action column.

1. Note the Date, Description, Payee, and amount spent or received.
2. Select the downloaded transaction to expand the view.
3. Review the Matching records found in QuickBooks. This is the possible matching transaction you've already entered in QuickBooks.
4. Select the link next to each match to get more details.
5. Make sure this is the correct match. In particular, review the Deposit to, Payment method, or Bank account fields on forms for the existing transaction in QuickBooks. The fields you see may differ depending upon the transaction you're matching.
6. If this is the correct match, close the open transaction.
7. Select Match.

You can on the line of the transaction in banking edit on the category. More detail can be found here in step 2 on this article.

Any questions let us know, we'd be happy to help further.