• Name, dates, location, and purpose of visit

• Name, date of birth, and passport number of the visitor

• Information on how transportation and local expenses are to be funded

• Information on the organization sponsoring the visit or meeting and relationship to
  the visitor

• Name, title, contact information (phone, fax, e-mail, web site) of person responsible
  for the visit or meeting, in case the consular office has further questions.

• That they have a residence abroad to which they intend to return

• That they intend to remain in the U.S. only for a specified limited period of time
  solely to participate in legitimate activities of B or visa waiver visitors (a non-refundable
  round-trip ticket or other confirmation is good documentation)

• Personal funding to support him/herself for the duration of his/her stay in the U.S.

If they will receive any kind of reimbursement for expenses incidental to the temporary
stay, the invitation letter should include language from the Foreign Affairs Manual of Citations [9 FAM 41.31 N8] as follows:

Aliens should be classified B-1 visitors for business, if otherwise eligible, if they
are traveling to the United States to:

• Engage in commercial transactions, which do not involve gainful employment in the
  United States (such as a merchant who takes orders for goods manufactured abroad)

• Negotiate contracts

• Consult with business associates

• Litigate

• Participate in scientific, educational, professional, or business conventions, conferences,
  or seminars

• Undertake independent research

[9 FAM 41.31 N11.1] A nonimmigrant in B-1 status may not receive a salary from a U.S. source for services
rendered in connection with his or her activities in the United States. A U.S. source,
however, may provide the alien with an expense allowance or reimbursement for expenses
incidental to the temporary stay. Incidental expenses may not exceed the actual reasonable
expenses the alien will incur in traveling to and from the event, together with living
expenses the alien reasonably can be expected to incur for meals, lodging, laundry,
and other basic services. 

[9 FAM 41.31 N11.2] …a B-1 nonimmigrant may accept an honorarium payment and associated incidental
expenses for usual academic activities (which can include lecturing, guest teaching,
or performing in an academic sponsored festival) if:

• The activities last no longer than nine days at any single institution or organization;

• Payment is offered by an institution or organization described in INA 212(p) [includes institutions of higher education]

• The honorarium is for services conducted for the benefit of the institution or entity;
  and

• The alien has not accepted such payments or expenses from more than five institutions
  or organizations over the last six months

USCIS has not yet issued regulations to implement this law. USCIS has acknowledged
in a memorandum to its field staff, however, that the law is in force and has instructed
USCIS inspectors to admit visiting international scholars who meet the conditions
set out in the law without new restrictions or documentary requirements.

Scholars arriving in the U.S. in B-1, B-2 or visa waiver status should have with them
letters from the institutions that will be providing them with honoraria. The letters
should note the services to be provided and the honoraria and travel reimbursements
offered. International scholars should be informed in advance of the limitations of
the B-1/B-2/visa waiver honoraria rule and cautioned to be careful not to exceed those
limitations.

For more information on honoraria and reimbursement, please click here.