Add Email field to Drupal using Email Field Module
By default, Drupal has many fields such as File, Image, List, Text, Long Text, etc. But, it doesn't have one of the most important fields: Email Field.
To add Email field to your Drupal site, you can use Email Field module.
Install Email Field module, and it is ready to be used. The module has no configurations. As you install the module, "Email" gets added to the list of field types you can add to site's content types.
One of the features of Email Field module is that it automatically validates the email addresses entered. For example, if the email entered is info@example, it will not be accepted.
Find of more on the modules' features on Email Field project page.