1. The resignation procedure of each unit is different. You don't have to worry about that. As long as the unit approves, you can leave your job smoothly.
As for your file, there are two places to go: 1. If you have a good relationship with this company and haven't offended anyone, I suggest you leave your file in the company first, and then go to school to go through the reassignment procedures after you find a job, and move to another work unit; 2. Return the files to the original talent center.
Note: Under normal circumstances, you can't get the documents yourself, and they are all sent by confidential means, so you should ask these questions clearly.
There is also the question of whether to take the civil service examination, and if so, we need to pay attention to the issue of becoming a full member and grading.