After passing the US visa interview in Guangzhou, where can I go to go through the mailing procedures to my home?

Embassy. After passing the U.S. visa interview in Guangzhou, you need to go through the formalities for mailing it to your home at the U.S. Embassy in China, that is, the location is the embassy. A visa is an endorsement or stamp by a country's sovereign authority on the passport or other travel documents held by its or foreign citizens to indicate that they are allowed to enter or exit the country's territory or pass through the country's territory.