Secondary addresses in Google channels work (almost) just like they do in email channels, so this article is lifted (almost) verbatim from here.
Secondary addresses (also known as aliases) allow you to send emails with a different “From:” address from the one on the account.
👀 Secondary addresses must be added and verified in your Gmail settings first.
Gmail has its own process for adding and verifying aliases (under Settings > Accounts and Import > Send mail as). If you add an alias here before adding it in your Gmail settings, Google will refuse to dispatch it.
G Suite users may need to contact their administrators in order to add aliases in their Gmail settings.
Your email provider may also be set up to receive incoming messages for many addresses in the same mailbox. If this is the case, be sure to add your alternate inbox addresses here.
- Display Name
The display name used for outgoing email.
Email display names value can be further customized in the Settings tab.
- The alias address to send outgoing messages as.
- The email account to be used when sending outgoing messages from this alias.
- Optional. Only visible from this dialog, the REST API, and the Rails console.