Using Sqlite how to maintain mailing service in windows phone 8.1

I created a login page and registration page in windows phone 8.1 app using sqlite database. When I login through the values from database how to create a mail system similar to normal mailing services like gmail using sqlite database.

(or)

How to save particular user data with respect to the user logged in. When the user login to the mainpage his data should be displayed.

Please answer the above both questions.