How to do it...

1. Navigate to the RegisterUser function and make the following changes.
2. Add a new string variable that accepts new input parameter named email from the request object:

         string firstname= inputJson.firstname;
         string lastname=inputJson.lastname;
         string profilePicUrl = inputJson.ProfilePicUrl;
         string email = inputJson.email;

         UserProfile objUserProfile = new  
          UserProfile(firstname,lastname,profilePicUrl,email);

1. Add the following code immediately after instantiating the message object:

        message = new Mail();
        message.Subject = "New User got registered 
         successfully.";
        message.From = new Email("donotreply@example.com");
        message.AddContent(new Content("text/html","Thank you so much 
         for getting registered to our site."));

        Personalization personalization = new Personalization();
        personalization.AddTo(new Email(email));
        message.AddPersonalization(personalization); 
        ....
        ....
        ....
  

        public class UserProfile : TableEntity
        {
            public UserProfile(string lastName, string firstName,string 
             profilePicUrl,string email)
            {
               ....
               ....
               this.ProfilePicUrl = profilePicUrl;
               this.Email = email;
            }
              ....
              ....
            public string ProfilePicUrl {get; set;}
            public string Email  { get; set; }
        }

1. Let's run a test by adding a new input field email to the test request payload, shown as follows:

        {
            "firstname": "Praveen",
            "lastname": "Sreeram", 
            "email":"example@gmail.com", 
            "ProfilePicUrl":"A Valid url here"
        }

1. This is the screenshot of the email that I have received: