On each Mailing List in the system, you can specify a custom look and feel for the Forward to a Friend, Unsubscribe, and Update Profile/Email System Pages.
Step 1: Click on the Edit Tab, Scroll down to Mailing Lists, and Select the Mailing List that you want to work with.
Step 2: On the Left Navigation bar for the Mailing List settings, you will see Custom Headers/Footers near the bottom.
Step 3: Select the Custom Headers/Footers tab.
Step 4: For each page you want to modify, select Display a Personalized Custom Page.
Step 5: On the following page, you can configure the HTML that will surround the content that we deliver on the aforementioned pages. You can use the editor to upload header images, footer images, and type in additional text. Be sure to leave the %%%splitpage%%% marker somewhere in the page, as this is where we will push our content.