Below we'll explain how to check or change the double opt-in setting for a Klaviyo list.
Open the list you want to use
Under the Opt-in Process section, you can select double opt-in or single opt-in
Click Update List Settings
Below we've also included a screenshot of the double opt-in setting. If you want to learn more about how double opt-in works in Klaviyo, see the help article here.