Use email aliases in Mail on Mac
An email alias is like a nickname. It can be used to help keep your real address private, or to give an alternative identity to your primary address without creating a new account. When you send emails using an alias, your email address isn’t shown to the recipients.
Create or change an alias
Go to the Mail app on your Mac.
Choose Mail > Settings, then click Accounts.
Select an account, then click Account Information.
Click the Email Address pop-up menu, choose Edit Email Addresses, then do one of the following:
Add an alias: Click , then enter a name and email address.
Edit an alias: Click the Full Name or Email Address field, then change the name or email address.
Remove an alias: Select an alias, then click .
Send an email from an alias
Go to the Mail app on your Mac.
Move the pointer over the From field in a message you’re writing.
Click the pop-up menu that appears, then choose an email alias.