Hi Richard and everyone else!
Overall it comes down to what email functionality you are using. If you are using MAPI, then an Outlook client will need to be installed wherever GP is.
If you are using Exchange, then you do not need Outlook, but you will run into issues if you have Basic Auth disabled, or MFA enabled.
This is true as of today, although we are reviewing changes for a future release of Microsoft Dynamics GP.
Reviewing what you are looking for, you can get this to partially work using Doc Attach. You can setup your items to have these attachments, then have them flow into the Invoices. Then when you email the invoices you can have the Doc Attach documents email along with it.
Dean walks through bits of this here:
community.dynamics.com/.../microsoft-dynamics-gp-2018-document-attachment-inquiry
This should be separate from how you decide to email, meaning MAPI and Exchange should both work. That said, if you want users to be able to attach documents from outside of GP to the emails, you will want to go with MAPI. When we email through Exchange, there is no way to edit the specific email before we send it. The MAPI functionality opens the emails in Outlook, allowing you to edit them and/or add attachments before then.
Let me know if you have any questions or concerns.
