Can't customize MP4 export settings

[tryingtolearn]

Hey guys, for some reason I don't know if I'm missing a check box?
I can't find a way to change the settings on the mp4 output please help

(I'm sure it's in front of my nose)

[GrassValley_SL]

If you select an exporter out of the recently used list you won't be able to modify it.

Go to the H254/AVC format and select it .