Hi @C0der, are you the developer of this web server?
Let's Encrypt uses a protocol called ACME to handle certificate requests and issuance. In order to get certificates from your web server, you'll need to speak ACME to the Let's Encrypt API endpoint.
You could use an existing ACME implementation, or write your own implementation.
The ACME protocol was standardized by the IETF. In addition to the original ACMEv1, Let's Encrypt newly supports ACMEv2, which is the only version of ACME with which Let's Encrypt will issue wildcard certificates. You can see more information about this at
including the "client developer information".
Most integrations use a standalone client (which may be called as a separate process) or client library, but you can also see the Caddy and Apache web servers' integrations which have support directly in the web server application. (The Apache support is mod_md - Apache HTTP Server Version 2.5 and the Caddy support is https://github.com/mholt/caddy/tree/master/caddytls. As both of these implementations are highly specific to their associated web servers, I'm just providing them as examples of how a web server could achieve native support for ACME if the developer chooses to purpose that path.)