In the beginning of the movie "Road to Ninja" you can see all of them writing requests to become Jounin and Tsunade had to deem them either ready or not ready to take on the rank (with parental permission, as Sakura's parents disagreed lol). In the end they were all rejected from furthering to Jounin as Tsunade did not deem them ready lol. Someone correct me if it was Chuunin they were signing up for! Either way I'm thinking that's the way it goes, and then if they are deemed worthy to further their rank, then they take the exams for said rank as well. Not sure but I hope this helped dear.
*Wait I remember it was Jounin and the families would write a recommendation letter for them. Naruto was sad because he didn't have anyone to write his recommendation letter, as most had their parents to do it for them.