How to introduce persons to embassy for visas who were invited by a firm?

Question

How to introduce persons to embassy for visas who were invited by a firm?

Answer 1

"Authorization letters" are NOT usually required; 90% of US business visas are granted based solely on the application form and the interview.  As long as the applicant knows and can explain lucidly where he is going, why, and on what schedule, no further documentation is required: an applicant who can't do that will not get the visa, whatever any letter he presents might say.   No document can take the place of an applicant who is clearly telling the truth.

Answer 2

Authorization letters coming from a firm must be presented by the applicant in order to be granted a visa.