The DS-11 applications, filed at a post office, get transmitted to the Passport Office by
some method [most likely EXPRESS MAIL, though maybe FEDEX

];
I'm in the process or renewing my passport. I'm going to the post office tomorrow so i can send priority mail (sadly i took too long so i have to pay the expedite fee as well) i did the rest by my self except the photos were done at the drug store.