It seems as though most have to apply for the OWP online. You have to wait until you have received the AOR (Acknowledgement of Receipt) of IRCC receiving the sponsorship application before you are eligible to apply for the OWP.
Previously a person could include the OWP application when submitting the hard copy sponsorship application. This was a great way to extend legal status while waiting for the PR process to complete, but it looks like that has changed.
https://www.canada.ca/en/immigration-refugees-citizenship/services/application/application-forms-guides/guide-5553-applying-change-conditions-extend-your-stay-canada-worker.html
"Normally, a work permit must be applied for prior to coming to Canada. Only in a few special circumstances presented in this guide can an initial work permit be applied for within Canada:
- you presently hold a valid study or work permit;
- you are the spouse of a study or work permit holder;
- you were previously authorized to work without a permit;
- you presently hold a valid Temporary Resident Permit;
- you are a refugee claimant or an applicant for permanent residence in Canada under section 207 of the IRPR, or
- you are a trader or investor, intra-company transferee or professional under the Canada-United States-Mexico Agreement (CUSMA)."
More info-
Applicants in Canada
207 A work permit may be issued under section 200 to a foreign national in Canada who
- (a) [Repealed, SOR/2017-78, s. 9]
- (b) is a member of the spouse or common-law partner in Canada class set out in Division 2 of Part 7;
- (c) is a protected person within the meaning of subsection 95(2) of the Act;
- (d) has applied to become a permanent resident and the Minister has granted them an exemption under subsection 25(1), 25.1(1) or 25.2(1) of the Act; or
- (e) is a family member of a person described in any of paragraphs (a) to (d).