Why is it difficult for users to know what to type into the text fields?

<html>
<body>
  <h3>Course Enrolment</h3>
<input type="text">
<input type="text">
</body>
</html>]]>
Because the placeholder attributes are missingBecause the input elements have no IDsBecause the type attributes are wrong

Users won't know what to type in because the placeholder attributes aren't set.