An open work permit authorizes a foreign national to work in Canada for any employer and in any location. If you are exempt from the Labour Market Impact Assessment (LMIA), then you are eligible to apply for an open work permit. 

If you want to extend or change your work permit, then you can apply 30 days before your current permit expires. The two types of open work permits are unrestricted open work permits and restricted open work permits. You are eligible for a work permit if you are the spouse or common-law partner of a foreign skilled worker or international student, an international student that graduated from a study program that lasted longer than 8 months if you’ve applied for permanent residence through the inland spousal sponsorship program, a participant in programs offered by International Experience Canada, or living in Canada as a refugee or protected person (and their family members).