I think it would be helpful to have some sort of "note" or "comment" field on an invoce. I think it could be used in the following ways:

1. When a partner pays an invoice on behalf of a client (either in the admin portal or impersonating the client), they could make a note of why they’re making the payment.

2. On custom payment links, add a parameter to allow passing the note text. One way I could see this would be useful is, for example, with QuoteWerks, the quote number could be included in the note field. This would allow the partner to easily identify the reason for the payment.

3. When a client is using a custom payment link, they might want to to note the reason for the payment.

Thanks for your consideration.