See Canvas Instructor Guide > Announcements for step-by-step instructions on creating and editing announcements.

You can also watch the following video tutorial:

519 - Announcements Overview from Canvas LMS on Vimeo.

IMPORTANT! If you are an instructor who has taught in Blackboard in the past, you are accustomed to automatically receiving an email when you post a course announcement. In Canvas, you must edit your notification preferences to indicate that you wish to receive an email of announcements that you have created; these are not sent by default. See Canvas Instructor Guide > How do I set my Canvas notification preferences? for instructions.