It should name the U.S. entity, state her Canadian citizenship, use the Appendix 2 profession wording, describe concrete professional accounting duties, and give the salary, the supervisor and the period requested. A letter describing a department rather than a job is the most common reason a well-qualified applicant is turned away.
Write the letter for the officer, not for the file
Hypothetical example: Aurélie is a chartered professional accountant at an East Ferris equipment dealership, and an American distributor wants her to build out its cost-accounting function. Accountant is an Appendix 2 profession met by a baccalaureate degree or by a C.P.A., C.A., C.G.A. or C.M.A.
designation, so her side of the analysis is straightforward. The letter is where these applications fail. It should sit on the U.S.
entity's letterhead, be signed by someone with authority, and say what she will do: standard costing across three product lines, month-end close, variance analysis, preparation for the annual audit. It should not describe the finance department in general terms, and it should not reach for words like consultant or advisor that invite a self-employment question. Attach the designation certificate and the degree parchment, since a membership card alone is not the designation.
If the assignment is genuinely eighteen months, ask for eighteen months and explain the project rather than requesting three years out of habit.