It is necessary to apply for VISA to enter in China before your departure!
Therefore, you have to follow this 2 steps:
1- Full fill the letter “Chinese Research Hospital Association (CRHA) invitation Letter for visa application at Congress 2019, download here
2- This letter needs to be send by email to Dr. Brian Wang, He will send it back to you with an invitation letter from the CRHA including a necessary and specific red stamp to get the Visa in your country. Dr Brian Wang – email: firstname.lastname@example.org