Time stamp Data entry in Excel

AHKOVC 

You need VBA for this. A formula cannot do what you want.

Right-click the sheet tab.

Select 'View Code' from the context menu.

Copy the following code into the worksheet module:

 

Private Sub Worksheet_Change(ByVal Target As Range)
    Application.EnableEvents = False
    ' Change C1 to the cell in which you want the time stamp
    Range("C1").Value = Now
    Application.EnableEvents = True
End Sub

 

Switch back to Excel.

Save the workbook as a macro-enabled workbook (.xlsm).

Make sure that you allow macros when you open the workbook.