To change the sender email of an existing campaign, follow these steps:
Select your campaign from the “Campaigns” tab.
Navigate over to the campaign settings by clicking the gear icon on the right side of your screen, next to the campaign title.
Select your desired email address from the “Sender Email” drop-down.
Click “Continue” to save the settings.
Note: You can only change the sender email for new opportunities that are added after a campaign’s launch. You will not be able to change the email for already launched opportunities unless you duplicate the campaign and change it in settings.