Edit text after user subscribers through a sign-up form

Hello!

How do I edit the text that appears after a user subscribes to a mailing list?

When a user subscribes they receive a notification that says "You can unsubscribe at any time using the Unsubscribe link at the bottom of every email."

Since we have a double opt-in process it would be good to notify users that they'll be receiving that email. So can you please tell me how I can edit this text?

Thanks!