A work permit is a written authorization issued by an office that allows a foreign national to engage in employment in Canada.
There are 2 types of work permits: open work permits and employer-specific work permits.
Open work permits
An open work permit allows you to work for any employer in Canada, except for an employer who is listed as ineligible on the list of employers who have failed to comply with the conditions or who regularly offers striptease, erotic dance, escort services or erotic massages
Employer-specific work permits
An employer-specific work permit allows you to work according to the conditions on your work permit. It is linked to a specific job, employer and location.
Canadian employers who wish to hire foreign workers approach ESDC (Employment and Social Development Canada) for approval of a Labour Market Impact Assessment Opinion (LMIA). An LMIA is a document from Employment and Social Development Canada/Service Canada that allows an employer to hire a foreign worker through the Temporary Foreign Worker Program (TFWP). The program objective is to assist employers who have demonstrated a need to fill jobs for which there are no qualified Canadians.