How can I Change the amount owed on a invoice after a partial payment

Hello there, @s-griggsfarrier.

Let me share some information on how you can manage your invoices and its payments.

QuickBooks Self-Employed only offers a simplified invoicing feature. Currently, the ability to apply partial invoice payments directly is not yet available since it doesn't have the Balance forward feature. What you can do is to duplicate the said invoice. 

Here's how:

1. Go to Invoices tab.
2. Locate the partially paid invoice.
3. Under the Action column, click the drop-down arrow beside Mark as paid link.
4. Choose Duplicate. 
5. Open the Original Invoice.
   1. Click Add Work.
   2. Enter the unpaid balance to show the amount of the partial payment your customer made.
   3. You can add a message or note to tell your customer that the remaining unpaid balance will be under a separate invoice.
   4. Hit Add to Invoice.
   5. Click Send Reminder.  
   6. Select Mark as paid to record payment. 
6. Open the duplicate invoice.
   1. Click Add work.
   2. Enter the details of the partial payment made.
   3. Make sure to put a negative sign on the amount.
   4. Hit Add to invoice.
   5. Click Send Invoice. 

Just a heads-up though, marking an invoice as paid does not automatically record the payments in your Transactions page. You have 2 ways how to record the partial payments.

• Add partial payments manually.
  1. Go to the Transactions page.
  2. On the right side above the list of transactions, click the Add Transaction.
  3. Enter the details for the transaction and select a category.
  4. Click Save.
• If the bank where payments were directed is connected with QuickBooks, just wait for it to be downloaded in the Transactions page. Then, categorise it as Business Income.

You can read through these articles to help you manage your income transactions:

• Connect bank and credit card accounts to QuickBooks Self-Employed
• About SA103F Categories

Keep us posted here if you have other questions or concerns. I'm always here to help.