How will I apply for visa if want to come and purchase goods in China

If you have a supplier in China, you can apply for a business M type for that.
First, you need to provide your passport and its copy, the application form, a passport-style photo and an invitation letter from your business partner, as well as other documents required by the consular officers.
Next, go to the embassy between 15:00 and 17:00 on every Tuesday or Thursday to make an appointment for the interview and submit the application.