I looked online & all the examples were not esential, atomic & minimal. They used jquery or provided no access to the actual source code.
So here is the minimal code :
<!DOCTYPE html>
<html lang="en">
<head>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/materialize/1.0.0/css/materialize.min.css">
<title>Demo of Date Picker</title>
</head>
<body>
Date: <input type="text" class="datepicker">
<script src="https://cdnjs.cloudflare.com/ajax/libs/materialize/1.0.0/js/materialize.min.js"></script>
<script>
document.addEventListener('DOMContentLoaded', function() {
let elems = document.querySelectorAll('.datepicker');
let instances = M.Datepicker.init(elems, {});
});
</script>
</body>
</html>
I would have found such a sample code helpful as opposed to complications with dependencies & multiple abstractions over JS.
This is what the date picker tool looks like (default):
