Cross-Origin Resource Sharing (CORS) is a mechanism that uses additional HTTP headers to tell browsers to give a web application running at one origin, access to selected resources from a different origin. A web application executes a cross-origin HTTP request when it requests a resource that has a different origin (domain, protocol, or port) from its own.
Let's say you need to add the following CORS headers.
Access-Control-Allow-Origin: https://example.com
Access-Control-Allow-Methods: GET, POST, PATCH, OPTIONS
Access-Control-Allow-Headers: Content-Type