Hello, @yaelle_ortiz and Welcome to the Canvas Community! The Canvas Student app works on the iOS platform (iPhone or iPad). It cannot be used on the MacOS. If you'd like to access Canvas through your Macbook Air, you can easily do so through a browser; Chrome is best, I find. What are the basic computer specifications for Canvas? , Which browsers does Canvas support?, and Mobile Guides - Canvas Student provide additional guidance.
I actually found a way to download the canvas student app on my Mac it’s through an app called Web catalog they make any website into an app