1. Where can my application for a Canada Immigration Visa be submitted?

That depends upon the Canadian immigration category under which you are applying. Candidates for the Federal Skilled Worker Class, Federal Skilled Trades Class and the Canadian Experience Class must first create an online profile, as these programs are processed through the Express Entry immigration selection system. Applications made to these programs are submitted online.
Under the Family Sponsorship category of Canadian immigration, applications should initially be submitted to the Case Processing Centre (CPC) in Mississauga, Ontario.
Under the Provincial Nominee Program category of Canadian immigration, or if you intend to reside in the province of Quebec, you must initially submit an application to the province in which you intend to reside.