"She wants to do sth" is correct. "She/he/it wants..." "She want to do sth" only works in a question: "Does she want to do something?" The verb "do" changes here: "she/he/it does..." "She wanna do sth" is poor English. In fact, using "she/he/it wanna" is incredibly poor. Not even heavy slang speakers would use that because it's so incorrect (slang still has to follow some kind of grammar to be understood).