Update README.md

Author: harshalparmar

README.md

@@ -1 +1,7 @@
-# 404-error
+# 404-error
+
+404 is an HTTP response code that indicates the server could not find the page requested. 404 error page informs users that they`ve followed a non-existent link or typed an address that doesn`t exist.
+
+Github pages: https://harshalparmar.github.io/404-error/
+
+![alt text](https://raw.githubusercontent.com/harshalparmar/404-error/main/404-error-page-img.png)