In the Drag & Drop Editor, select the Plain Text Template to create a campaign email containing only text.
Go to the Templates section, and click "New" to create a new template. Under it, click on "Drag & Drop Editor".
Then select -> Plain Text
Now you can create a template that contains only texts.
MailExpress generates a default footer based on your company name and the mailing address you've provided in the "Account Information" section under “Setting”. You can also customize it by following the instruction here.