Assuming it’s recorded as one payment in your bank, you can go into the payment option and it will list everything linked to it.
If you go to Purchases > View Payments:
Find the one in question:
You can see that the top on is allocated to two invoices. Click ‘View Details’, and you’ll see something like this:
You can then click ‘Print’ which generates a PDF.
Anther way you can do it, is go to the supplier record, and click ‘View’ and select ‘All Payments’:
Hope that helps!