what is the use of script tag in html code example

Example 1: what is the use of script tag in html

<script>
  //Insert JS scripts here
  var html
  html = "You can use the <script> tag to incorporate JS code into your HTML code"
  console.log(html)
</script>

Example 2: script tag in html

<script>
  // Write JS here
</script>

<script src="link/to/js/file.js"></script>