I've created a custom registration form which accepts extra fields like mobile number, address etc and stored into user meta values. This is working fine, now I have to add a functionality of sending email to admin with all the meta value details whenever a new user registers on the site.
You can get the last inserted id at the time of registration and with this id get the user meta by meta keys you assign and send mail with details.
wp_send_new_user_notifications automatically sends the registration info of new users to admin. Just try this line of code and it should do the needful.