You can edit the email template for your campaign by clicking on the drop-down tab next to your campaign and selecting 'Edit Template'.
Templates can also be accessed by visiting the Templates section on the left of your account.
Editing the Template
Use the options on the right side of the editing view to customize the company name, logo, messaging, etc. Explore each section by clicking on the carrot icon.
Click Update at the bottom of the page once finished.