Settings

Invoice email delivery

Same options as on Email Accounts. Send from is the Graph mailbox (the visible From address).

At least one email account configured

Send from (From) — Microsoft 365 mailbox *

Forward to (To) *

CC (optional) Comma-separated.

Microsoft 365 setup

Credentials are stored per mailbox on the Email Accounts page (tenant, client ID, secret, user email). Your admin registers one Azure app with Mail.Read and Mail.Send (application permissions, admin consent).