Whatever the default editor is. Filip answered my question above, it is can be found in a sub-menu by clicking the gear symbol at the bottom of the editor
I was about to say the same thing @Filip Němeček mentioned with one tiny addition.
The icon to add the canonical url is only active if you are using the rich + markdown editor but if you are using the basic markdown editor you will have to add the canonical url to the front matter.
You can check the following post for more information.
Which editor version are you using basic markdown or rich + markdown?
Whatever the default editor is. Filip answered my question above, it is can be found in a sub-menu by clicking the gear symbol at the bottom of the editor
I was about to say the same thing @Filip Němeček mentioned with one tiny addition.
The icon to add the canonical url is only active if you are using the rich + markdown editor but if you are using the basic markdown editor you will have to add the canonical url to the front matter.
You can check the following post for more information.
A Beginners guide to the DEV editor
Habdul Hazeez ・ Dec 14 '19 ・ 11 min read
You can consider the post a living document and it's updated as DEV UI changes.