Ohk I contacted one agency they saying in online you have option to choose option outside Canada or inside
Then you can choose outside and attach a letter explaining situation and it goes
Is it right or just false?
If they say that, could they share the link (to official GoC website) so that you can check? (They won't because it's not true, or they've misrepresented the context)
Ditch that agency, go online, and get/check the forms yourself. It's not that hard to apply. But you must do it from within Canada.