Hello,
With the default emulator you'll not be able to change any setting without editing the configuration file in SSH or through the console.
However, if you go to "Advanced settings" -> "Advanced emulator configuration" -> "Nintendo 64" and then you change the emulator for "Libretro" and the core to "GLUPEN64" and game aspect to "16/9" it will be good.
With this emulator you can also modify setting on the fly with "hotkey + B" or "hotkey + A" depending how you configured your controler.