Private Sub Workbook_BeforePrint(Cancel As Boolean)
Dim Sht As Worksheet
For Each Sht In ThisWorkbook.Worksheets
Sht.PageSetup.RightFooter = Environ("Username")
Next Sht
End Sub
ALT+F11 to open VB editor. Double click 'This Workbook'
On the right hand side panel select 'Workbook' from the left dropdown and
'Before Print' and paste it in there.