Customs clearance responsibility depends on your agreed Incoterms. Under FOB (the most common term), the supplier handles export clearance in China, and you handle import clearance at your destination. Under EXW, you handle everything including Chinese export clearance. Under CIF, the supplier covers costs to your port, but you still handle import clearance.

In practice, most buyers work with a customs broker in their country to handle import clearance. The broker prepares documentation, calculates duties, and liaises with customs authorities. Your freight forwarder often provides brokerage services or can recommend one.