Steps:
Go to dashboard.
Click on the settings button.
Select marketing option.
Click on the add identity button.
Choose the email option. Add your email details and hit the next button.
Check your email and verify to add another email for custom branding. Then check on the recheck status button to verify successfully.
Click on the drop-down menu and select the email option.
A pop-up will appear. Choose your added email. Write your email and hit the send button.