HTTP headers are the core part of HTTP requests and responses, carrying information about the client browser, requested page, server, and more.

• General Headers: Apply to both requests and responses (e.g., Connection).
• Request Headers: Contain more information about the resource to be fetched or about the client itself (e.g., User-Agent).
• Response Headers: Hold additional information about the response, like its location or about the server providing it (e.g., Server).
• Entity Headers: Contain information about the body of the resource, like its content length or MIME type (e.g., Content-Type).