Here is the code. Just put it into a regular module and run it form there.

Sub Test()
    Dim bottomA As Integer
    bottomA = Sheets("itbof").Range("A" & Rows.Count).End(xlUp).Row
    Dim bottomL As Integer
    bottomL = Sheets("itbof").Range("L" & Rows.Count).End(xlUp).Row
    Dim rng1 As Range
    Dim rng2 As Range
    For Each rng1 In Sheets("itbof").Range("A2:A" & bottomA)
        If rng1 <> "" Then
            Cells(rng1.Row, 3).Value = "A"
            Cells(rng1.Row, 20).Value = "N"
        End If
    Next rng1
    
    Sheets("itbof").Range("I2:I" & bottomA).Select
    Selection.NumberFormat = "0.00000"
    
    For Each rng2 In Sheets("itbof").Range("L2:L" & bottomL)
        If rng2 <> "" Then
            Sheets("itbof").Cells(rng2.Row, 9).Value = Sheets("itbof").Cells(rng2.Row, 12).Value * 1.08
        End If
    Next rng2
End Sub