When you use MailChimp's signup forms, we require the double opt-in process. There's not a way to turn off or otherwise disable the email that asks folks to confirm their subscription to your list, but the Final "welcome" email which is sent after opt-in has been confirmed can be disabled.
To disable the Final "welcome" Email:
- Navigate to the Lists page.
- Click on the list drop down and select Signup forms.
- Select the General forms option.
- Select the Final "welcome" email from the forms and response emails drop down menu.
- Uncheck the Send a final welcome email box.
You can also disable the Final "welcome" email by navigating to the Lists page > Settings > List name & defaults and uncheck the box next to Send a final welcome email.
While it's possible to manage your own signup process using the single opt-in method, we strongly recommend using the double opt-in method instead. Here's a great example of why we recommend using double opt-in over single opt-in. We've also seen that double opted-in lists have much higher engagement levels over time. This means more opens and clicks and fewer bounces and unsubscribes. Check out this blog post for even more info.