Let's look at several HTTP requests to learn the basic structure of these messages, and how the various elements communicate important information from the client/browser to the API service.
Follow the instructions at HTTPie to download the CLI tool and follow along.
Install: Link
RUN:
Get all the Request header / body and Response header and body:
http get https://api.github.com/users/zhentian-wan
Get only request printed:
http get --print=HB https://api.github.com/users/zhentian-wan
See the options: Link