You’ll find a new tab called List building tools under Settings > List settings. The List building tools tab replaces the previous Subscription forms tab. Please check it out more here
Subscription forms allow you to add subscribers who sign up to your newsletter on your website.
A subscription form is added to a page on your website, and connected to your admin console, so that when a user signs up in order to receive your newsletter, he is automatically added as a subscriber to the MailUp system..
You can use standard or custom subscription forms:
These forms are ready to use without any modification.
You can customize your form, so that it matches the general look of your website.
Create a new tab to load a newsletter signup form on your Facebook page