How do I make a clickable link on blogs and quizzes?

If you highlight the thing you want to link, you will see a bar at the top of the box that has all the options like Bold, Italicize, Underline, etc. Hyperlinking is the last one. Click it, paste the URL, and that's it!

For quizzes, you need the actual HTML. It's as follows:

< a href = "URL HERE" > Whatever you want as the clickable link here < /a >

Remove all of the spaces in this except the one between the "a" and "href", and the ones between the "Whatever you want as the clickable link here", obviously.