I think you can only do it online once you get the AOR. I sent the OWP with my application so I sent to Mississauga, but from what I’m reading:
“
For spouse or common-law partner work permits, send your application to:
Case Processing Centre in Edmonton
Immigration Refugees and Citizenship Canada
c/o Work permits for spouses or common-law partners, Station 777
9700 Jasper Avenue NW, Suite 55
Edmonton, AB T5J 4C3”
I read it in the link below, but maybe somebody else that has done it can confirm:
https://www.canada.ca/en/immigration-refugees-citizenship/services/application/application-forms-guides/guide-5553-applying-change-conditions-extend-your-stay-canada-worker-paper.html#5553E7