The action attribute indicates where form data should be sent. For example, <form action="/submit-url"></form> tells the browser that the form data should be sent to the path /submit-url.
Add an action attribute with the value https://freecatphotoapp.com/submit-cat-photo to the form element.
I’ve edited your code for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.
You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.