If you want to send out your marketing campaign from a different email address, then you can add them as an alias to your campaign. Below steps will help you to add other email address to your campaign.
1) Go to Marketing and then select Broadcast Campaign under Email Marketing.
2) Click on Add option 
at the right hand side screen to create a new broadcast campaign.
3) On Campaign setup screen, click on From Email section and select “Verify another email address“.
4) Type in another email address and click on Send Verification Email option.
5) Log into your email account and verify.
6) Now you will be able to send out emails from your different email account.
This email address will be saved under the From email dropdown list for later use.