You can do this with Zapier. Here's how:
Create a new (public) Distribution List - you can read all about this HERE
Add contacts to your Distribution List
Use the 'New Contact added to Distribution List' Trigger when creating the Zap
For the Action, select the appropriate Action (e.g If you want to send Contacts to Email Automation platforms like Autopilot or Mailchimp, I'll choose the Autopilot or Mailchimp Apps related action i.e. Add New Contact in Autopilot OR Add/Update Subscriber in Mailchimp.)
To get started with Zapier, click here.