Icons can help in several ways to support your content presentation. Icons can:

put content in a nutshell
draw attention
increase readability

Icons can draw attention, but at the same time, they can help you structure content and separate different functions.

You won't see your icon until the page is Published

After pasting your code, if you select the "Rich Content Editor" you will not see your icon.

Code

The yellow highlighted area is where you will insert your icon code.

Publish your page & voila...icon!

When we publish the page, a calendar icon will appear:

This is what it looks like in the HTML editor:

Special Icon Codes

icon-stats
icon-paperclip
icon-media
icon-address-book
icon-reset
icon-announcement
icon-analytics
icon-student-view
icon-calendar-day
icon-trash
icon-speed-grader
icon-copy-course
icon-export-content
icon-import-content
icon-discussion
icon-discussion-reply
icon-peer-review
icon-discussion-new
icon-edit
icon-home
icon-settings
icon-compose
icon-flag
icon-video
icon-audio
icon-outdent
icon-indent
icon-outdent2
icon-indent2
icon-forward
icon-warning
icon-filmstrip
icon-rubric
icon-rubric-dark
icon-check-plus
icon-rss
icon-rss-add
icon-quiz
icon-question
icon-drop-down
icon-minimize
icon-end
icon-add
icon-info
icon-check
icon-clock
icon-calendar-month
icon-x
icon-refresh
icon-off
icon-updown
icon-user-add
icon-group
icon-star
icon-replied
icon-hour-glass
icon-assignment
icon-message
icon-note-dark
icon-note-light
icon-tag
icon-next-unread
icon-search
icon-lock
icon-unlock
icon-folder
icon-toggle-right
icon-toggle-left
icon-link
icon-lti
icon-text
icon-timer
icon-pin
icon-like
icon-collection-save
icon-collection
icon-group-new
icon-group-new-dark
icon-user
icon-standards
icon-search-address-book
icon-facebook
icon-facebook-boxed
icon-linkedin
icon-twitter
icon-twitter-boxed
icon-github
icon-skype
icon-wordpress
icon-pinterest
icon-gradebook
icon-document
icon-module
icon-mini-arrow-up
icon-mini-arrow-down
icon-mini-arrow-left
icon-mini-arrow-right
icon-arrow-up
icon-arrow-down
icon-arrow-left
icon-arrow-right
icon-email
icon-instructure
icon-ms-word
icon-ms-excel
icon-ms-ppt
icon-pdf
icon-apple
icon-windows
icon-android
icon-heart
icon-upload
icon-download
icon-text-left
icon-text-center
icon-text-right
icon-mature
icon-prerequisite
icon-educators
icon-calendar-days
icon-materials-required
icon-not-graded
icon-peer-graded
icon-bookmark
icon-printer
icon-image
icon-expand
icon-collapse
icon-invitation
icon-muted
icon-unmuted
icon-plus
icon-zipped

Source

Edwards, P. (2017, March). Canvas Icons. Retrieved June 13, 2019, from https://canvas.instructure.com/courses/787387.