Jeremy Nunez there are a couple of ways to accomplish this:
1.) Use My Tokens--if you have a "master folder" in marketing activities where all of your programs, campaigns, etc reside, you can insert a text or rich text MyToken in the footer of each email from the master folder. Then when a value needs to be updated, simply update the MyToken value.
2.) User Snippets--you can replace an element in footer of each email with a snippet. Then when a value needs to be updated, simply update the snippet and approve using no-draft.