You may use the following steps to examine HTTP headers sent to and from Apache or NGINX on your cPanel server. One use case would be to verify that your server is sending the correct Expires Headers after you have enabled them with the steps from in the following article:
1. Navigate to the website in Google Chrome
2. Right-click anywhere on the page
3. Click "Inspect", or "Inspect Element"
4. Click on the Network tab
5. Reload the web page
6. Click on the first item in the list of requests. This would typically be the request for the actual website and not one of the requests for secondary resources.
A sub-window will open that will show both the requests headers that your browser sent to the webserver, as well as the response headers that the webserver sent back to your browser.