Sage has the facility to attach another file to the invoice to be viewed by the customer.
When the customer receives the email with the invoice, there are 2 ways 2 view the invoice.
1st is to go straight to the attached invoice PDF. If the customer does this, they won't see the other attached files.
2nd way to view is to click on the blue banner in the middle of the email. that reads 'View My Invoice'
This will then show the pdf of the invoice and all other attachments
If the customer opens the attachment via the 1st option they won't be able to view the other attached items,