STUDY PERMIT is for studying in Canada, while F1 is for studying in US, there is no way to switch from one to another since Canada and US are two different contries.
For study in US, you must apply for a school. Once you get admission, that school will issue I-20 to you for F1 visa application. Maybe you are holding B2 in US, if you didn't declare that you intended to study in US when you cross the border, you will not be able to change your B2 to F2. You must apply for a F1 visa outside US.