Email forwarding allows you to set up virtual email addresses that contain your custom domain and forward messages to the email address you choose.
For example, if your email address is firstname.lastname@example.org, and you added the domain example.com to your site, you can create a forward from email@example.com to firstname.lastname@example.org. Emails sent to email@example.com will arrive at firstname.lastname@example.org
Managing email forwarding
Your email forwards live under Store → Domains in your dashboard. Every custom domain you added to your site will have a Manage Email link next to it. Click on Manage Emails to add or remove email forwards for that domain.
To set up a new email forward, enter the new email address in the first field and your existing email address in the second field. After adding an email forward, you will receive an email with a link to confirm it. This email will be sent to the existing address, to verify that you own it. Once you click on the confirmation link in the email, the email forwarding will be activated:
You can create up to five email forwards on your custom domain. To delete an existing email forward, click on the Remove button.
Changing your From address
By default, your emails will go out with your existing email address in the From line. That is, users will still see your existing email address on emails you send them, and not the new email address you set up here using email forwarding.
The specific email address that recipients will see in emails coming from you depends on how your email client is configured. Most email clients will let you configure this in the Settings, Preferences or Options section, under Accounts or Sending.
See here for detailed instructions on setting this up for some popular email clients: