Make row that automatically adds newest month + 2 nearest future months

Simple AutoFill

Sub Updatemonths()
    Dim x As Long
    With Worksheets("Sheet1").Cells(4, 4).Resize(, 2)
        .Cells(2).Value = DateAdd("m", 1, .Cells(1).Value)
        x = DateDiff("m", .Cells(1).Value, DateAdd("m", 2, Date) - Day(Date) + 1)
        .AutoFill .Resize(, x + 1)
    End With
End Sub