Looping through unkown sheet names

The bit that you have at the end of post #8 does not reference the worksheet(z) when selectin Range("A1:K1") so it will always reference the activesheet rather than looping through them. Try something like:

Sub macro_2()
Dim ws As Worksheet
For Each ws In ThisWorkbook.Sheets
    ws.Rows("1:2").Insert shift:=xlDown
    With ws.Range("A1:K1")
        .HorizontalAlignment = xlCenter
        .VerticalAlignment = xlBottom
        .WrapText = False
        .Orientation = 0
        .AddIndent = False
        .IndentLevel = 0
        .ShrinkToFit = False
        .ReadingOrder = xlContext
        .MergeCells = False
        .Merge
    End With
Next ws
End Sub