With GDPR passing a few months ago, managing your contacts details and getting consent to send them communications is very important.
We will need to get the mail merge from the Preference Center to insert it into the button.
First, click into the body of your campaign and go to Insert, Recipient Details, Recipient URL's, Preference Center.
Double click the Preference Center hyperlink and copy the mail merge in the URL box
Next, go back into your campaign content and insert a button. Click create a link and paste in the mail merge we copied earlier