what different between Ill2cp and mono2x when build IOS

Hi guys, i’m in trouble with this problem, my game is so light(18mb at android) but when i build it to IOS using ill2cpp it up to ~~200mb, OMG so i choosed mono2x and size are reduced, but i dont know what different between 2 options, who can expain for me? thanks so much

I also need an answer to this.