There are 2 types of work permits available in Canada:
Employer-specific work permit – In such work permits, the candidate is open to working only for a specific employer.
Open work permit – In such permits, candidates are allowed to work for any listed and eligible employer.
IS IT IMPORTANT TO BE IN CANADA TO APPLY FOR A WORK PERMIT?
No, it is not important to be in Canada to apply for a work permit as it can be applied from outside as well. In both cases, conditions are requirements are different.