how to get form data in express code example

Example 1: How to send form data from react to express

const url = localhost:4000/api/users/register;
const usersData= [];

let getData = () => {
axios.get(url)
   .then(res => usersData.push(res.data))
   .catch(err => console.log(err.data))
}

Example 2: how to get data send from a form express

const express = require('express')
const app = express()

app.use(express.urlencoded())