If you want to permanently exclude a customer from receiving remarketing emails, you can update their person record in the system.
To exclude a customer from remarketing emails:
Go to Data > Visitors.
Enter the customer's email address and select Search to find their record.
Select Exclude from Email Remarketing in the top-right corner.
If the customer's email address is not in the system, submit an unsubscribe request to create a record and exclude them from remarketing:
Expand the User menu and go to Settings > Triggers and Messaging integrations.
Select Unsubscribe Link.
If a redirect URL is not set up, enter your website's homepage address (or a confirmation/thanks page), then select GO.
Copy the URL for your account's unsubscribe link, presented on the screen, into a text editor.
Replace [email] with the customer's email address.
Copy and paste the full URL (with the email address at the end) into a web browser and visit the page.
To confirm the address is unsubscribed, go to Reports > All Reports > Visitors.
Enter the customer's email address and search for their record. You should see a message confirming the exclusion.