Chandra,
the only way I know of is to use a Worksheet_Change Event procedure.
Using your example the following worked for me

Private Sub Worksheet_Change(ByVal Target As Range)
Sheets(2).Range("A6").Formula = ActiveSheet.Range("A6").Formula
End Sub

I put this Sub into the Sheet 1 module.

It only works one way. The formula on Sheet 2 changes when you change
the formula on sheet 1, but not the other way around.

Hope this helps
Ken Johnson