wanna是want to的口语，表示想的意思。wanna属于缩略结构，后面要加动词。wanna侧重于口语表达。wanna = want to 比较口语化 I'd like to 也表示我想做... I'd like to...比want to更委婉。
wanna的用法
wanna = want to 用于口语中。
Example:
标准：I want to go to school.
口语：I wanna go to school.
标准：I don't want to eat it.
口语：I don't wanna eat it.