Adding an Opt-in Checkbox to the WooCommerce Checkout Page
If you have the WooCommerce plugin installed, you can add an opt-in checkbox from MailPoet to your checkout page so your customers can subscribe to your mailing list and receive emails sent from the MailPoet plugin.
All customers will be automatically added to the WooCommerce Customers list by default, but their status as subscribers will depend on your settings in the MailPoet > Settings > WooCommerce tab.
Opt-in on checkout enabled
You can also select other lists to automatically add your subscribers to, so they will be added to the WooCommerce Customers list and to a different MailPoet list of your choice. Leave it empty if you want the subscribers to be added to the WooCommerce Customers list only.
Users who check this checkbox on checkout will be added to the WooCommerce Customers list (and any other list of your choice) as "Unconfirmed" until they confirm their subscription via email. Users who didn't check this checkbox will be added as "Unsubscribed".
In the "Checkbox opt-in message" option, you can customize the opt-in message that will be displayed on the checkout page. The WooCommerce opt-in default message and all strings are translatable.
Please note that transactional emails sent from WordPress or WooCommerce itself or any 3rd-party plugin will be sent regardless of checking or not this checkbox. This opt-in checkbox is exclusively related to the emails created and set up using the MailPoet plugin.
When the checkout form is displayed, the checkbox should be checked by default for users who have already subscribed and unchecked for unsubscribed or unknown ones.
This means that if you've already been added to the mailing list as "Subscribed", the checkbox will be checked by default for you every time you go through the checkout page.
Opt-in on checkout disabled
If the "Opt-in on checkout" option is disabled, meaning there's no checkbox displayed on the checkout page to subscribe to a mailing list, the subscribers will be added to the WooCommerce Customers list as "Unsubscribed".