Hi JoMarshall
Thanks for your post.
Currently, MYOB only allows us to attach documents to purchase, this feature is not supported. Thank you for your suggestion/ideas. We'll relay your feedback to the relevant team. Rest assured that we are doing our best to improve and provide excellent service to our valued customers.
Feel free to post again if you need further assistance in the future. We're happy to assist.
Cheers,
Cel