My sound wont export with the mp3,can not find the master choice?
Export is a menu option in File - you need to get the display that should be at the top of your screen back. I can't tell you how to, as it's a Mac...
On output sound there is no "master" choice, how can i find it?
That's the Master output that you've renamed as Mix. If you look at the mixer view, you'll find that it's the last channel on the right. To export your mix, you have to do as I said above - go from File>Export and follow the path according to exactly what you want to export. I changed the output channel on this system to 'Mix' temporarily to show you exactly what you're looking for - it's this:
Perfect, thank you! 🙂