'Wanna' is slang for 'want to' or 'want a'. Never write it. Native speakers do sometimes say it, but only as an unintentional result of speaking quickly while mumbling. Only ever write it when quoting someone. I've seen a lot of English learners that think saying 'wanna' makes their English sound more natural, or that 'wanna' is an real abbreviation of 'want to' and 'want a'. It doesn't and it's not. Do you know how you mispronounce words when you try to say a tongue twister too quickly? People say 'wanna' for the same reason. 'Wanna' is the most extreme version. You often hear sounds in between 'want to' and 'wanna' like 'won-ta' or 'won-oo'.

1st thing to note is difference in syntax: "I want to (& verb)" vs "I wanna (& verb)". 2nd is "I want to & verb" is standard English, yet "wanna & verb" is used in spoken English and is slang. Refrain using the second one when talking to friends or foes :) , for instance. Examples: 1. It's so hot today, I want to go to the beach! (standard) 2a. I wanna go to the beach, wanna come? (colloquial) 2b. Yea (Yes), I wanna (wanna go), whatcha (what) gonna (are you going to) do about it? [Giving someone attitude, oddly enough about going to the beach :) ] (My Spanish is zero, sorry there's just English I can use. I wanna, but I just can't!)

wanna (informal) = want to (formal)

'Wanna' is the same as 'want to', but it's an informal version

Want = want Wanna = want to I Wanna go to the park /I want to go to the park.