Is it possible to include additional field(s) within a payment remittance to our suppliers so they can allocate a payment from us easier?

Hello Ian

Thanks for joining us in the Community!

The remittance advice on QuickBooks Online pulls from the bill payment you can add a comment in the memo section on the bill payment which will pull through  into the same place on  the remittance but you can not add columns/boxes into just the remittance itself.

Emma