Putting the files in the Education Bureau has no effect on your postgraduate entrance examination. It's nothing more than going to the Education Bureau to transfer your file directly when the graduate school needs it after you are admitted.

The files of fresh normal students are generally kept in the Education Bureau for one year, and then transferred to the Talent Exchange Center of the Personnel Bureau. You don't have to go through this procedure yourself. The Education Bureau will directly transfer the graduates' files to the Personnel Bureau.

I hope my answer can help you.