Normally, applying for a study permit inside Canada may have a shorter processing time. However, only some people can apply for a study permit from inside Canada.

You may be eligible to apply for a study permit inside Canada if you are currently in Canada and one of these applies:

1. You’re a Ukrainian national or family member of a Ukrainian national
2. You have a valid study or work permit
3. Your spouse, common-law partner or parent has a valid study or work permit
4. You’re a minor child in primary or secondary school
5. You’re an exchange student or visiting student
6. You completed a short-term course or study program required to be accepted at a DLI
7. You or your spouse, common-law partner or dependent child has a temporary resident permit (TRP) valid for 6 months or more
8. You’re being sponsored to immigrate, and you already applied for permanent residence (if you’re eligible)
9. You or your spouse, common-law partner or dependent child are subject to an unenforceable removal order
10. You’re the spouse, common-law partner, or dependent child of:

• an athlete on a team based in Canada
• a member of the media
• a member of the clergy
• military personnel on duty in Canada or
• an accredited foreign representative

11. you’re a refugee claimant in Canada or a family member of a refugee claimant in Canada

If these situations do not apply to you, you will have to apply for a study permit outside Canada.

Source: https://www.canada.ca/en/immigration-refugees-citizenship/services/study-canada/study-permit/apply.html