This action is called a Conversion. A conversion doesn’t just mean buying a product or service, you can set an email submit as the conversion goal in Microsoft Ads. Whenever a person submits his/her email in the email submit form of a website then a conversion tracking pixel is fired which will display the action performed as a Conversion.
This question is a part of the Microsoft Advertising Certified Professional exam. You can find all the answers with full explanation for this exam in our Microsoft Advertising Certified Professional Exam Answers page.