What is a Quebec Letter of Acceptance in Canada?
Both international students and temporary foreign workers who want to permanently stay in Quebec can apply for Quebec Acceptance Certificate or Quebec Certificate of Acceptance. It is indeed the key to entering Canada for work or studying purposes in the Quebec province. This autonomy can select students and workers under the different economic, as well as, immigration programs.
Quebec Acceptance Certificate for Temporary Foreign Workers
You may be wondering, what is a letter of acceptance in Canada? Well, apart from LMIA, a CAQ is required by applicants who are working on a temporary work permit.
People working in Quebec do not require CAQ for a work duration of 30 days or less. Plus, CAQ is unnecessary for candidates whose jobs do not require LMIA. Skilled workers who have a Quebec Certificate of Selection (CSQ) will certainly not require a CAQ to obtain a work permit.
However, what is the difference between CSQ and CAQ? Now, CSQ is important to authorize the applicant to apply for obtaining permanent residency in Quebec. On the other hand, CAQ will only ensure the applicant’s temporary stay in the province. That’s why once an applicant has CSQ, they will not have the necessity of CAQ.

Lastly, in case, if IRCC exempted a work permit from a foreign national, then she/he will not need a QAC.

Quebec Acceptance Certificate for International Students
Studying in Quebec needs a CAQ even before acquiring the Canadian Study Permit. After getting the approval letter from DIL, you can proceed to apply for CAQ.
But if your work is only going to last for 30-days or less, the candidate does not have to avail of a CAQ.
For students who are exempted from applying for a study, the permit will not require CAQ.
You can further apply for a study permit extension until the CAQ is valid.