A job offer letter is a document that a Canadian employer gives you (as a temporary worker). It explains the details of your job.A job offer letter from a Canadian employer is a crucial document for obtaining a work permit and potentially immigrating to Canada. In most cases, the employer must send you: the job offer and a Labour Market Impact Assessment (LMIA) number; or; the offer of employment number. You should read your job offer letter carefully. This stream is open to foreign workers in and outside of Canada. Employment Letter A job offer letter is a document that a Canadian employer gives you (as a temporary worker). They sent an email congraluting me and asking if I am interested to take up the Job. I replied saying yes for sure.