A signed letter on company letterhead naming the profession, describing the professional duties, giving the salary, start date and requested period, and confirming that the company has reviewed her degree. She carries that with the parchment, an official transcript and proof of Canadian citizenship.
One letter carries most of the weight, so ask for a draft early
Wendy should request a draft of the support letter weeks before travel and read it against the profession list. The letter needs the U.S. entity's legal name and address, her full name and citizenship, the profession stated in the list's own words, and duties written concretely enough that a reader unfamiliar with feed businesses can follow them.
It should give the salary, confirm the role is temporary and state the period requested, which may not exceed three years at a time. Marketing language and revenue targets do not help. Alongside it she carries the parchment, an official transcript, a résumé and proof of Canadian citizenship, with originals rather than photocopies wherever she has them.
If any document is not in English, a complete certified translation is required. Asking for the draft early also reveals whether the employer understands the arrangement it is proposing.