We recommend you to apply for a Chinese business/visiting visa (F) or study visa (X2). To get the visa you will need an official letter from the school, which we will send to you when the application fee is received.
You would want to check their website before going there in person, check their working day/hour, prepare all the required materials and make an appointment. And in some countries, you do not even to go in person, just submit the application online and mail your passport. Find the nearest Chinese embassy.