1. Enter reading page -> Tools;
2. Select Hyperlink on the toolbar, then you can drag a range for the link;
3. There you can choose to redirect it to different destinations: Page, URL and Email;
4. Click Go to finish the setting;
5. If you want to make the link area visible or invisible, click Page Display and turn on or off Highlight Links, or you right click anywhere in the PDF and tick Highlight Links.