Copenhagen - Shanghai - Hong Kong 80 hours

Your itinerary and your citizenship are definitely eligible for 144 hours visa free transit. Please, just use correct terminology because you will travel on 144 hours visa free transit and you will not apply for any kind of visa. Of course, you will fill out the form at the relevant counter, present your tickets and accommodation booking in hard copy, but there will be no visa. One more detail... Keep in mind that your flight from Copenhagen to Shanghai should not have any additional landing within mainland China. Also, it is perfectly fine to arrive at Pudong and depart from Hongqiao airport.

Thank you for the answer.
Since I will stay with a friend I dont have a hotel reservation to show.
Will that cause a problem?

There will be no problem if you have your onward ticket to HK.