16 days

Work permits and student permits are not visas. If you extend your work or study permit, IRCC will not automatically issue you a visitor visa. You must apply separately for a new visitor visa.

You can only apply for a visitor visa in Canada if you meet these requirements:

• already live in Canada,
• have a valid study or work permit,
• want to leave and return,
• and have a visitor visa that's expired, about to expire, or was only valid for 1 entry

If you have already left Canada and need to apply for a new visitor visa then you have to follow the steps to apply for a visa from outside of Canada, not the steps to apply from inside Canada. 

Applying through paper? Check out visa processing time for visitor visa inside canada through paper