Before doing anything else, make sure to check out the "How to ask" page.
Just a heads up, if you include nothing inside a link element, it won't output anything. Make sure to at least have one letter or content within it.
<a href="https://www.facebook.com/FacebookDevelopers"> A </a>
This code will display the letter A as a hyperlink. Remember that whatever you want linked should be placed inside the <a>
tag. Here's another example with an image as a link:
<a href="https://www.facebook.com/FacebookDevelopers">
<img src="random-image.png" alt="test" height="50" width="100">
</a>
To delve deeper into how to use the a tag, click here