My supplier has already sent me a copy of their business license and ISO certificate. Why do I still

Because documents supplied by the supplier are not independent evidence — they are self-reported. Business licenses in China can be forged, altered, expired, or belong to a different entity with a similar name. ISO certificates can be borrowed from another company, photoshopped, or issued by an unaccredited body. We have seen all of these scenarios. What we do is verify the document against the official source: we check the registration number in the government database, confirm the legal status is currently active, verify that the registered business scope actually covers what they are selling you, and confirm the legal representative matches. If the certificate is genuine, the verification will confirm it. If something is off, you will know before it costs you money.