Subscription Software

Hey, everyone!
I have an input bar, with a button, of course, on my site. It serves as a subscription box. I’m wondering if there is a service I could use that would collect emails and allow me to send the list of emails a message at once? Surely this exists, right?

Like formspree, which allows users to send you messages simply by adding their service.

Thanks in advance!

EDIT: I’m using mailchimp, which is exactly what I was looking for. This is solved.

Fun fact: the first Open Source For Good project was to create an emailing tool.