If the marriage certificate is in English or French, you may need to get it authenticated or legalized, but otherwise you can use it for the application. If the marriage certificate is in another language, you’ll need to get a certified translation for your sponsorship application.
If your future wife has an eTA, she can come to Canada before you submit the application (this is called “inland” sponsorship). If she cannot get an eTA, you have to sponsor her outland.
You should submit the sponsorship application after you are married.