Permissions: You need Billing permission to work with invoices.
If you need to apply one payment to multiple invoices, you can split the invoiced amount across each invoice.
- Link the line to the first invoice.
- In that same invoice, click the line you want to split.
- Reduce the Invoiced Amount to the amount you want to be allocated to this invoice, and click the Save Invoiced Amount button.
- The Remaining amount will appear as an uninvoiced item on the billing account, which you can link to the next invoice.