I am hoping to get a six month F visa for a consultation service. The university in China is asking me what they should write and whats important to mention in their invitation letter? Should the invitation letter be written with direction to me or to the embassy? When I make money out of business transactions there, how much tax do I have to pay on the earnings? I dont have a formal company, I am their liason agent, so what kind of letter should I write to the embassy for application cover letter?