The Newsletter plugin can integrate with many form managers or form designers to collect subscriptions directly from those forms.
A subscription option can be added or the forms can be designed specifically for the newsletter subscription. Fields in the form can be mapped to the subscriber’s fields (email, first name, last name, extra fields, lists, …).
Most of the integrations with form builders can be configured with a per-form custom welcome email, designed with the Newsletter composer and with statistics collection.