Single Maps display one Mapbox Studio style at a time. You need only to specify a style.
Multi Maps accept multiple Mapbox Studio styles, and titles for those maps. These will appear on an overlay on your map with a simple radio button switcher.
Both Single and Multi Map shortcodes accept all other attributes, such as zoom, center, height, etc.
Example
Single Map
[wp_mapbox_gl_js style="mapbox://styles/mapbox/streets-v10"]
Multi Map
[wp_mapbox_gl_js styles="mapbox://styles/mapbox/outdoors-v10,mapbox://styles/mapbox/light-v9" titles="Outdoors,Light"]