wanna is contraction of "want to" , purely colloquial. never use it in writing... we write the sound of our speech, when we say "want to", we say it fast, so it sounds like "wannuh" can't is a contraction of can not, and it is acceptable for use in formal writing, though "can not" is often more suitable for formal situations.

The word "wanna" is not standard spelling. It simply represents the way "want to" often sounds in spoken English. You should not write "wanna" in formal English. "Cannot" and "can not" both mean essentially the same. "Can't" is used in informal writing and speech.

Ok. Wanna is a slang or contraction; wanna is the contraction of want to, for example: "I want to travel" is the same "I wanna travel". Wanna sometimes is considered wrong, but, it is used. Other examples: gonna is the contraction of going to. Can't and cannot is the same, because can't is the contraction of cannot. :D.