Outside of a payment, an Email Address is probably the single most important thing you collect from your customers. It not only allows you to build a customer list for marketing purposes, but it's often critical to your customers actually receiving the product they purchased.
As a business owner, a customer making a typo when entering their email address can cause major customer service problems for you. Thankfully, Email Confirmation Fields are here to ensure that you collect the right email address every time.
To enable an Email Confirmation Field on your Product Page
Open your Product's edit page and head to the Checkout Design tab:
Scroll down the Fields section and check the Email Confirmation box:
Click Save Changes and you're good to go! Here's what that the Email Confirmation field looks like on a live Product Page (using the Launchpad template):