Yes, you can select this option in your Canvas discussions.  However, please keep in mind that sometimes students will work around this requirement by deleting their posts. To prevent students from being able to use this "workaround" you can change your course settings to disable students' ability to delete their posts.

Further resources:

• How can I require students to post to a course discussion before they see replies?
• How do I allow students to edit and delete their own discussion posts in a course?