Many devices that send emails on your behalf utilise SMTP services to send those emails. If an email account is provided through Office 365, emails can therefore be routed through that account.
For SMTP, the following settings must be used:
Username: Office 365 Username
Password: Office 365 Password
Bits to Note
Office 365 enforces TLS 1.2 on SMTP connections. Your device must support TLS 1.2 or later to work in this setup.
The Username must be for a licenced Exchange Online user. If the user needs to send as another address, you should grant that user permissions to send as that address. Sent Items will be placed in the mailbox of the original user.
If an account is configured with Multi-Factor Authentication, they may need to use an App Password unless the SMTP application supports Modern Authentication.