To link a word or phrase, mark it with your cursor. Then click on the “link” button in your button bar on top of your editor content area and paste in the URL you would like to link to. The link appears like this:
[I’m a link to Matterial](https://www.matterial.com/)
In the document view, the URL is hidden, showing only the link:
So, every link can also be simply typed, without using the button.