Carriers --- They are real shipping companies, owning vessels, a big boss in the process. After cargos are delivered to their territory (port, loading on board), it usually is hard to ask them to make changes (especially BL is already issued.) In China, few shippers contact with carriers directly, but forwarders do. 

Documentation
Invoice --- Suppliers will give you an English version, they will make Chinese version for China customs clearance,too.

Packing list --- Make it detailed and readable, not only for the customs clearance, but also for your conenience. 

Product certifying documents--- Different country customs usually require different documents. For example, safety certificates like CE, Rohs are a must to export electronics to Europ,UL for US, TUV/GS for Germany. These documents are required in destination customs clearance. What specific documents are needed? Check with your country import departments or talk to your suppliers.

Certificate of Origin --- CO/FORM A/FORM B/FORM E/FORM K/FTA, etc. Some countries require it. 

Bill of lading --- BL for short, issued by a shipping company. One BL means your cargos on board. Losing the BL almost means losing your cargos. So keep it very carfully.

Trade terms

There are many professional trade terms, such as FOB, CNF, CIF, FAS, FCA, and so on. Each term means different responsibility for sellers and buyers. You need pay special attention. What terms should be used? It depends on your negotiation with your suppliers. The most common and popular terms for China suppliers are EXW, FOB, CNF, CIF. As smart as you are, you must know what these terms mean, or know where to find their rules. You can text us for details, too.

In sea freight shipping, trade terms define who pay for and be responsible for trucking, pors, freights.