Update Purpose inside READme

Author: congmul

README.md

@@ -1,3 +1,13 @@
 # React
 
+## Table of Contents
+- [Purpose](#purpose)
+- [Installation](#installation)
+- [Usage](#usage)
+- [Project Structure](#project-structure)
+- [Contributing](#contributing)
+
+## Purpose
+The primary purpose of this frontend service is to provide a user-friendly interface for maintaining API specification that adhere to OpenAPI Specification (OAS) 2.0 and 3.0 standards.
+
 [Link](https://orange-cliff-0a124561e.5.azurestaticapps.net)