How to Auto Fill Default, Auto Fill Series in Excel using VBA

Excel VBA Macro to Auto Fill Default, Auto Fill Series
MODEL 1:
'Macro To AutoFillDefault :
'This Is A User Friendly Macro which Works Based on User Selection
Sub FillDefault()
For X = 1 To 100
Selection.AutoFill Range(ActiveCell.Offset(X, 0), ActiveCell.Offset(0, 0)), xlFillDefault
Next X
End Sub

'Macro To AutoFillSeries :
'This Is A User Friendly Macro which Works Based on User Selection
Sub FillSeries()
For X = 1 To 100
Selection.AutoFill Range(ActiveCell.Offset(X, 0), ActiveCell.Offset(0, 0)), xlFillSeries
Next X
End Sub
-----------------------------------------------------------------------
MODEL 2:
Macro To AutoFillSeries :
Sub AutoFillSeries()
'If You Know Active Cell Then You Can AutoFillSeries As
'Syntax 1:
Cells(2, 1).AutoFill Range("A2:A100"), xlFillSeries
'Syntax 2:
Cells(2, 1).AutoFill Destination:=Range("A2:A100"), Type:=xlFillSeries
End Sub

Macro To AutoFillDefault :
Sub AutoFillDefault()
'If You Know Active Cell Then You Can AutoFillDefault As
'Syntax 1:
Cells(2, 1).AutoFill Range("A2:A100"), xlFillDefault
'Syntax 2:
Cells(2, 1).AutoFill Destination:=Range("A2:A100"), Type:=xlFillDefault
End Sub

Thanks,Tamatam