Good day, joyce-lyn.

For me to provide the correct solution to your concern, can you tell me more about it? Are you trying to send a credit note?

I'll be keeping an eye for your response. Keep safe!

Yes Adrian, 

I am trying to send an organisation a credit note as a way to track royalties that I owe them.  

Including attaching evidence for them. 

Kind Regards  Joyce-Lyn

Thanks for getting back to me, Joyce-Lyn.

You have me to help you send a credit note. Let me guide you with these steps:

1. From the + New button, select Adjustment note.
2. Select a Customer name.
3. Enter their Email.
4. Enter the PRODUCT/SERVICE, QTY, RATE, and AMOUNT.
5. Select their GST.
6. Scroll down and click the Attachment icon.
7. Select the file and then click Open.
8. When done, click Save snd send.

I've also added this article that has the lists of transactions that can keep attachments: Attachments in QuickBooks Online.

Feel free to get back to this thread if you need my help. Take care always.