Run Macro Only On Visible Worksheet

Hi, Emily03,

if the code is placed in ThisWorkbook it should read like

Private Sub Workbook_BeforePrint(Cancel As Boolean)
Dim ws As Worksheet, wsT As Worksheet
Set wsT = Sheets("Productivity")
For Each ws In Worksheets
  If ws.Visible = xlSheetVisible Then
    ws.PageSetup.CenterHeader = "&f " & wsT.Range("C1").Value & Chr(13) & "&a"
  End If
Next ws
End Sub

Please note that you should use code-tags for displaying procedures.

Ciao,
Holger