I haven't returned to China yet. Can I continue to apply for an entry visa in Canada?

A better way is to ask your roommate or neighbor to bring your signature, and then UPS will mail it to your address in China.

You can continue to endorse when you return to China, but it is not recommended that you do so. It's best to wait until the result of this visa comes down.

Before returning home, bring materials that need to be signed again, such as school certificate, grade certificate, course certificate for next semester, bank deposit certificate, etc.

Toronto to Ottawa should be received in 1 week at the latest. Check whether your visa has been sent online.

Best wishes.