Create a User and Password for ADO.net and SQL SERVER Authentication
Please go through below links :

https://stackoverflow.com/questions/16386610/how-do-i-create-a-new-user-in-sql-server-2012-that-i-can-use-in-a-connection-str

https://msdn.microsoft.com/en-in/library/aa337562.aspx

https://stackoverflow.com/questions/1601186/sql-server-script-to-create-a-new-user