If it is shipped by sea, it should be packed first. You can lift empty boxes with container trucks at the port, put clothes into boxes at home and send them to the port. You can also find a car to take these things to the port and pack them at the port.
After loading, the agent will apply for inspection and customs declaration. After release, the container will be shipped to China. Just find a local domestic freight forwarding company to help you import.
It's best to pay the sea freight in advance, because the price of sea freight abroad is lower than that in China. If the cost is involved, the average international moving business of a 20-foot container in China is about1.5,000 ~ 20,000. I wonder how much the United States will charge you.
The shipping time depends on which port in the United States, generally about 40 days, and the port clearance is generally about 3 days. You can pick up the goods after release.