How would I make text appear under a link?
<div class="login">
    <a href="">Login
    <p>Access your profile here</p>
    </a>
</div> 
Where the login triggers the p to show?
Do I need to use the p or something else?
that's simple just add title attribute in tag
<a href="http://www.studyofcs.com" title="Tricks Site">Studyofcs</a>
The following style makes the p visible on hover:
.login a p {display:none;}
.login a:hover p {display:block;}
<div class="login">
    <a href="">Login
        <p>Access your profile here</p>
    </a>
</div> 
Or if you want the whole link including p inside stay visible together on hover use the following:
.login a p {display:none;}
.login a:hover p {display:block;}
.login a:hover {display:block;}
<div class="login">
    <a href="">Login
        <p>Access your profile here</p>
    </a>
</div> 
Simple Html Tooltip
<a href="https://stackoverflow.com/" title="Where Developers Learn, Share, & Build Careers">stackoverflow</a>
Tooltip Using Bootstrap :
<!DOCTYPE html>
<html lang="en">
<head>
  <title>Bootstrap Example</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
  <h3>Tooltip Example</h3>
  <p>The data-placement attribute specifies the tooltip position.</p>
  <ul class="list-inline">
    <li><a href="#" data-toggle="tooltip" data-placement="top" title="Hooray!">Top</a></li>
    <li><a href="#" data-toggle="tooltip" data-placement="bottom" title="Hooray!">Bottom</a></li>
    <li><a href="#" data-toggle="tooltip" data-placement="left" title="Hooray!">Left</a></li>
    <li><a href="#" data-toggle="tooltip" data-placement="right" title="Hooray!">Right</a></li>
  </ul>
</div>
<script>
$(document).ready(function(){
  $('[data-toggle="tooltip"]').tooltip();   
});
</script>
</body>
</html>
You can achieve hover tooltip By Bootstrap+JQuery also :
<!DOCTYPE html>
<html lang="en">
<head>
  <title>Bootstrap Example</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
  <h3>Tooltip Example</h3>
  <a href="#" data-toggle="tooltip" title="Hooray!">Hover over me</a>
</div>
<script>
$(document).ready(function(){
  $('[data-toggle="tooltip"]').tooltip();   
});
</script>
</body>
</html>
In case you are using bootstrap you can use the following:
<a class="login" href="" data-toogle="tooltip" title="Access your profile here">Login</a> 
You just can use old title argument, works well, the shortest solution
` is being *part of* the link. Anyway, this should work: `.login a:hover p { display:block }`
– Hashem Qolami Apr 01 '15 at 20:25