How to generate random ID via API?

I found in the article that there is an option to generate random ID. But how can I do it via API?

Can you elaborate on what you meant by random ID? All contents that are generated via web-app or API will have a random entry ID.

Hi fanny,
I created content model “User” and online form with some fields like Name, Phone, Address etc. When user (call him Joe Doe) submit this form it sends to the contentful model. So my question is where can I find this random id (this particular user Joe Doe)? Because I see only these fields that I created: Name, Phone, Address etc…