what is actually ADO.NET and its relation with MVC C#?

ADO.NET : It is an API which helps to connect Database from your application either Web or Windows. MVC is used to develop web application which is UI purpose. And your MVC application will use ADO.NET to connect to get data from Database. Follow below links that may help you: 

 

http://www.c-sharpcorner.com/UploadFile/0c1bb2/insertupdatedelete-in-Asp-Net-mvc-5-using-ado-net/

 

https://gallery.technet.microsoft.com/scriptcenter/CRUD-Operations-In-ASPNET-9b9c922d

 

https://www.aspsnippets.com/Articles/ASPNet-MVC-ADONet-Tutorial-with-example.aspx