A job offer letter is a document that a Canadian employer gives you (as a temporary worker). It explains the details of your job.This gives the candidate an idea of what to expect and helps clarify any details that may have been misunderstood or overlooked during the interview process. A job offer letter from a Canadian employer is a crucial document for obtaining a work permit and potentially immigrating to Canada. Example of a non-valid job offer. A sample letter offering a job contingent upon the results of a background check or other criteria. Do not mix up a job offer with an employment or work reference letter. I have never applied for anything in the states. If you receive a valid offer of employment from a Canadian employer, you could enhance your position in the pool of Express Entry. Do you require the Office of Immigration to issue a Letter of Support for a work permit?