Created Invoke Method (markdown)

Invoke-Method.md

@@ -0,0 +1,33 @@
+# Invoke Method
+
+The Invoke Method feature has been supported since Caterpillar Proxy version 0.1.5.17. This feature allows you to remotely call functions defined on the server.
+
+First, create a request in JSON format as shown below. Save it as a file named phpversion.json.
+
+```json
+{
+	"jsonrpc": "2.0",
+	"method": "relay_invoke_method",
+	"params": {
+		"callback": "phpversion",
+		"args": []
+	},
+	"id": ""
+}
+```
+
+Next, use curl to perform a test to call the server's function remotely.
+
+```sh
+curl -X POST --data "@phpversion.json" -H "Content-Type: application/json" -H "User-Agent: php-httpproxy/curl" http://YOUR_HOSTNAME/
+```
+
+You should see the phpversion output as shown below.
+
+```json
+{"jsonrpc":"2.0","result":{"status":200,"data":"8.2.18"},"id":""}
+```
+
+## Report abuse
+* ActivityPub [@gnh1201@catswords.social](https://catswords.social/@gnh1201)
+* abuse@catswords.net