Hello Hanna,
Without being able to see the assignment, my guess is that the instructor has not set the assignment to accept text entry submissions.
If the assignment is set to allow text entry submissions, it will display a "Text Entry" tab, as shown in this article:https://community.canvaslms.com/docs/DOC-14129-4212833572
If you don't see a "Text Entry" tab when attempting to submit the assignment, you will want to contact your instructor about the allowed submission types.
Also, make sure that you are using the most recent version of whatever web browser you are logging in with, since older browser versions can sometimes not display things correctly in Canvas.
Mike
