Search by header name or purpose to find whether it is a request or response header, what it controls, and an example value you can use.
It tells the recipient the media type of the body, such as application/json or text/html, so the content is interpreted correctly.
It sets caching rules like max-age, no-cache and no-store, controlling how long and whether browsers and proxies store a response.
Access-Control-Allow-Origin and related Access-Control-* response headers grant cross-origin requests permission to read the response.