Is it necessary to have an invitation letter from an American business party for the visa of American B 1? If it's just sightseeing, then B 1 can't do it, right? In addition, the B2 visa is valid for

Is it necessary to have an invitation letter from an American business party for the visa of American B 1? If it's just sightseeing, then B 1 can't do it, right? In addition, the B2 visa is valid for 1 year. 1, business visa B 1 must hold an invitation letter from the United States, without which it is impossible to apply for B 1.

2. A tourist can't do B 1, but if you hold B 1, you can visit anywhere after your business activities in the United States.

Yes, as long as you return to China within the specified time.

3.B 1/B2 visa is valid for one year and can be used multiple times.