insert auto date when paste value in cell

You can do this with a macro. The following code should be placed in the module for the worksheet:

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Column = 2 Then Cells(Target.Row, 3) = Date
End Sub

This code checks every time any cell on the sheet is changed (the only event that's suitable) to see if the changed cell (Target) is in column B. If it is, it changes the cell in the same row but in column C to the current date.