As an instructor, you can edit a page that you created.

As a student, you can create and edit a page that you created in a group. How do I create a new page in a group?

By default, only instructors (teachers) can edit course pages. However, you can set a default preference for specific users to edit and contribute to the page in the Course Settings Course Details tab. How do I set details for a course?

The following link contains information about editing a Page in a Canvas course space: How do I edit a page in a course?