Hello @cmarin ...
I'm a little confused by your question. Are you asking about third-party LTI apps that can be integrated with Canvas? If so, those apps are generally not the same as apps that you download to your iPad (although the word "app" or "apps" is used both places). LTI apps that integrate with Canvas may require some additional setup (either at the course level or at your school's account level) in order to use them. And, some LTI integrations have a cost associated with them. Sometimes, depending on the LTI integration, those can be pricey. But, some integrations are free. Here are a couple links for you on LTI integrations that are available:
You can also visit the EduAppCenter website for a complete listing of all LTI apps that are available for Canvas.
I hope this helps. Please let me know if you have further questions.