To  Add an Unsubscribe Button to Your Campaign Email, follow the below steps: 

Step 1: Log in to your account. 

Step 2: From the left-hand menu, go to the Campaigns section. 

Step 3: Select the campaign name from the list where you want to add the unsubscribe button.

Step 4: Scroll down to the Template section.

Step 5: Add or edit your campaign content in the editor.

Step 6: Click on Available Tags (located near the editor).

Step 7: Scroll down in the tags list and find [UNSUBSCRIBE_LINK].

Step 8: Copy [UNSUBSCRIBE_LINK] and paste it at the bottom of your campaign content.

Step 9: Click on Save and Next to update your campaign.