Asterisk on either side of the word, words or part of the word you wish to italicize. Two asterisks on will getcha a bold

Yo check out giant size put a # and one space in front of words as the first thing on a line for words you wanna make effin big: eg

# giant size

becomes

giant size

Edit Edit: ~~use two tilde to like this to cross words out~~

and fix your oopsies