Starting in 2024, Notions Marketing began the process of setting up Klaviyo to better track our customers email marketing habits. 
Our existing email marketing send list had to be moved over to the new system, but with evolving global marketing consent regulations, we had to have the customers opt-in and then confirm (double opt-in) to add them to the new system. 
We achieved this with multiple sends of this email to direct them to the form to fill out on our website. Then, Klaviyo would send the confirmation email and our new list would be created!