Hello @KellyL618 ,
This is already available in accounts, so I'll be moving your post from our Product Ideas board to our Questions & Discussions board. Depending on your account type, different levels of automation paths can be setup to automatically message new subscribers. You can either setup a New Subscriber email that triggers from new contacts added specifically via a sign up form, or setup more advanced Added-to-List automations that trigger from any new addition to the specified lists, regardless of source.
See also:
Getting started with the Automation Path Builder
Understanding triggers in the Automation Path Builder
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