How to auto-generate PDF attachment to invoice

Hi All,

I'm using SAP Tempo in my current role and have just introduced invoices being sent automatically to our customers via email.

I'm looking for instruction on how I can get SAP to auto-generate a PDF attachment of the invoice in the Attachments so that when a customer calls in, myself or a colleague can open it up straight from the Attachments rather than having to output it again.

I'm not terribly experienced SAP user, so I would appreciate if someone could provide some help in as simple terms as possible.

Thanks so much in advance.