You can create and use email signatures for each email address individiually.
Writing your email signature
When you are in Accounts tab, click "Show Details" for the email address you want to add signature.
You can use links, images and anything other details you want to include in signature.
After writing youe signature copy, click Save.
Include your signature in your email copy
You can use the signature whereve you see fit in your email copy.
When you start your campaign, it will be included in the email copy!
Happy sending!