Learn HTML by Building a Cat Photo App - Step 1

Tell us what’s happening:
Describe your issue in detail here.

  **Your code so far**
<html>
<body>
  <h1>Hello World<h1/>
</body>
</html>
  **Your browser information:**

User Agent is: Mozilla/5.0 (Linux; Android 11; SM-A022F) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.131 Mobile Safari/537.36

Challenge: Learn HTML by Building a Cat Photo App - Step 1

Link to the challenge:

hi, welcome to the forum.
If you are stuck on this exercise, take a look in this post to see if it helps you move forward:
step 1