Choosing the opt-in method for the registration form.

The MailChimp addon allows you to choose which opt-in method you wish to use.

Method 1: Automatically add users to a list when they signup

Navigate to  Users -> WPUM Settings -> Extensions in your WordPress dashboard and locate the "Opt-in method" setting and enable the "Automatically add users to a MailChimp list when they register." option.

Once enabled, all users, upon successful registration, will be added to a MailChimp list that you've enabled. 

Note: if you've enabled multiple lists, you must enable only one list. Otherwise WPUM will choose the first list that it can find.

Method 2: Let users choose to which list they want to signup

Navigate to   Users -> WPUM Settings -> Extensions in your WordPress dashboard and locate the "Opt-in method" setting and enable the "Allow users to opt-in to subcribing to a MailChimp list when they register." option.

If you want to allow users to signup to multiple lists, you must enable the option "Allow users to select multiple lists" from the "How many lists" setting and you should also enable multiple lists from the "lists" table.

Once these settings have been configured, the registration form will display one or more checkboxes depending on how many lists you've enabled like in the example below:

It's recommended that you enable the Double opt-in setting to comply with MailChimp regulations.