Difference between sheet, module and thisworkbook in excel

I don't want to duplicate code in sheets, so right now i have

'##Sheet1
Sub test()
   callThisSub(parameter)

   callThisSub2(parameter)   
End Sub

'##Module1
callThisSub(parameter)
    ...
End Sub

'##thisworkbook
callThisSub2(parameter)
    ...
End Sub

callThisSub works
callThisSub2 doesn't work, do I need to define it differently? the code is workbook specifik so I guess I should have it in thisworkbook and not in a module?