Option Explicit

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
   TestInRange
End Sub

Option Explicit

Function InRange(Range1 As Range, Range2 As Range) As Boolean
' returns True if Range1 is within Range2
Dim InterSectRange As Range
    Set InterSectRange = Application.Intersect(Range1, Range2)
    InRange = Not InterSectRange Is Nothing
    Set InterSectRange = Nothing
End Function

Sub TestInRange()
    If InRange(ActiveCell, Range("H6:H81")) Then
        ' code to handle that the active cell is within the right range
        ActiveCell.Offset(0, 1).Value = ""
    Else
        Exit Sub
    End If
End Sub