Cloaking

Cloaking in SEO (Search Engine Optimization) is a practice where a website shows different content or structure to human users and search engines. Here’s a simple example to explain it:

Let’s say you have a website about cats. When people visit your website, they see lots of pictures and information about cats, Products for cats, but when Google comes to see your website he only see articles about cats. This is Content Cloacking. content Cloacking is against Google Guidelines.

But if you only change the structure of the page then it is legal white hat Cloacking, and it is totally fine. When you change the structure of your content for mobile this is cloacking for example 

The reason some people do this is to try to trick the search engine into ranking their website higher. Or they are doing a website about a specific type of content that they do not want to show Google, Bing or other Search Engines