The article is about U.S and not Canada. Also yes, you can stay in Canada while apply + wait for the final decision, but if you get rejected, you have to leave. Also in your application, you have to state where you applying from. I find the Canadian immigration system clear and fast, login, input data, pay, wait.

you can renew the same permit without, but you can't go from one type of permit to another (student to working prof in my case) without flagpoling; you also can't go from a visa to a permit without flagpoling