I'm sure there's a better way without activating/selecting - but this works
until you get something tidier!

Sub insert2rows()

Dim wkSheet As Worksheet

For Each wkSheet In ActiveWorkbook.Worksheets
wkSheet.Activate
Range("B1").Select
Selection.EntireColumn.Insert
Range("A1").Select
Selection.EntireColumn.Insert
Next wkSheet
End Sub