i need information regarding medical treatment

Ehsan, you mean you want to come to China for medical treatment? If so, you need to apply for an S2 visa. To apply for it, an invitation letter or diagnosis certificate from a relevant hospital in PRC is required. Besides, you need to submit a financial support proof, your passport, passport copy, application form, color bareheaded photo, and maybe an invitation letter from duly authorized unit. After all the documents are prepared, you should go to the embassy or consulate to submit the application.