how to insert multiple rows at the same time using mvc!

If you are using ADO.NET
 
DataTable dt = new DataTable();  
dt.Columns.Add(new DataColumn("Id", typeof(string)));  
dt.Columns.Add(new DataColumn("Name", typeof(string)));  
foreach (var entry in entries)  
    dt.Rows.Add(new string[] { entry.Id, entry.Name });  
  
using (SqlBulkCopy bc = new SqlBulkCopy(connection))  
{   // the following 3 lines might not be neccessary  
    bc.DestinationTableName = "Entries";  
    bc.ColumnMappings.Add("Id", "Id");  
    bc.ColumnMappings.Add("Name", "Name");  
  
    bc.WriteToServer(dt);  
}  

For EntityFramework

YourContext.Employees.AddRange(  
   yourEmployeeList  //List
   );

For Dapper

using (var conn = new SqlConnection(cs))  
{                      
    var affectedRows = await conn.ExecuteAsync("insert into tblEmployee values(@Name,@Salary)", yourEmployeeList);  
}  
//Note:- parameter Name must match to your Employee class properties name