Find out job offer requirements for Express Entry and who needs a Labour Market Impact Assessment (LMIA). This generates an offer of employment number, starting with the letter "A," which you'll need when applying for your work permit.A job offer letter is a document that a Canadian employer gives you (as a temporary worker). It explains the details of your job. In this article, we outline how to get employment reference letters for Canadian immigration, including the accepted format for work reference letters. Learn everything about job offer letters for immigration, including eligibility criteria, required documents, and the process. Learn how to apply for permanent residence in Ontario if you are a skilled foreign worker with a job offer in Ontario. Your Canada job offer should be written on official company letterhead with contact information, including registration and contact number.