All tags need to be closed, either with an ending tag or they're "self-closing". For example, for links within a page:
<!-- the id isn't used for re-directing but can be used for CSS styling -->
<a href = "#section1" id = "link1">Click to go to Section 1</a>
<!-- the ID in the <div> is used for referencing within an internal page
but also can be used for CSS styling -->
<div id = "section1">
I chose to link to a <div> but you can link to other HTML elements instead.