Free entry transit visa to enter Shanghai

I will be flying from the uk to Hong Kong embarking on cruise ship visiting one Chinese port Shanghai for approx 14 hours we then continue onto Japan disembarking in Tokyo and flying back to the Uk. Can you please inform me if I have to fill out any paperwork required to be sent to the PRC Embassy for a transit entry permit prior to leaving the Uk or do I apply for the free transit at port of Shanghai. Many thanks.
SuziB. X