You need to bring some materials, such as a valid personal passport, a personal signature photo, two one-inch photos, company letters, etc. You can apply for a visa directly at the embassy. An American visa is an endorsement on a passport or other travel document held by an American or foreign citizen, indicating that the holder is allowed to apply for entry into the United States. It can also be said that it is an endorsement certificate issued to them. American visas can be divided into two categories: immigrant visas and non-immigrant visas, and each category can be divided into many subcategories. Holding an American visa may not be successful in entering the United States, and the US Customs and Border Protection (CBP) will finally decide to grant the port entry rights.