Copy the URL (CTRL+C on PC or CMD+C on Mac) of the webpage you would like to hyperlink.
Navigate to the content page within your site manager in which you will be adding a hyperlink.
Highlight the text you would like to hyperlink:
With your text highlighted (estate taxes in the example above), press the icon above the editor that shows the globe with a closed chain link:
This will prompt the Hyperlink Manager to pop up:
In the URL field, you will paste (CTRL+V on PC or CMD+V on Mac) the URL that you copied in Step 1.
The Target dropdown seen in the screenshot above will default to None. This will open the hyperlink in the same window. If you are linking to an external site, this should be set to New Window.
Once you are done with Steps 6 and 7, you can click OK at the bottom of the Hyperlink Manager. This will take you back to your content page with the newly added hyperlink (see estate taxes in screenshot below). You will know that it was successful by the change in text color within the editor:
Do not forget to hit the blue save button at the bottom right of the content page screen. It's always good practice to visit the edited content page and complete a hard refresh by clicking CTRL+R together on your keyboard to see the change take effect.