how to send data from frontend to backend with node js - node.js

Question

Frontend
I use ejs to create forms
<form action="/users/create" method="POST">
<div class="row">
<div class="col-2">
Id Advance Requisition
</div>
<div class="col-6">
<input type="text" class="form-control" id="IdAdvanceRequisition" name="IdAdvanceRequisition" required/>
</div>
</div>
<div class="row">
<div class="col-2">
NoRef
</div>
<div class="col-6">
<input type="text" class="form-control" id="NoRef" name="NoRef" required/>
</div>
</div>
<div class="row">
<div class="col-2">
NIK
</div>
<div class="col-6">
<input type="text" class="form-control" id="Nik" name="Nik" required/>
</div>
</div>
<input type="hidden" class="id" name="id" />
Back
<button type="submit" class="btn btn-primary btn-sm">Save</button>
</form>
router for the router on the frontend, why can I only use post and get? whereas to delete and update you have to use DELETE and PUT
const express = require('express');
const user = require('../controllers/user')
var cors = require('cors')
const router = express.Router();
router.get('/index', user.getUsers);
router.get('/add', user.getAdd);
router.post('/create',cors (), user.createUsers);
router.get('/detail/:id', user.readUsers);
router.post('/delete/:id', cors (), user.deleteUsers);
router.get('/edit/:id', user.detailUpdate);
router.post('/update/:id',cors (), user.updateUsers);
module.exports = router;
controllers for add
createUsers : async (req,res) => {
try {
const Backend = await getBackend();
const dataBackend = await Backend.json();
const user = {id: uuidv4(), IdAdvanceRequisition: req.body.IdAdvanceRequisition, NoRef: req.body.NoRef, Nik: req.body.Nik};
dataBackend.push({...user, id: uuidv4()});
fetch('http://localhost:8000/users', {
method: 'post',
body: JSON.stringify(user)
})
console.log(`Data with the id: ${user.id} added to the database!`);
res.redirect('/users/index');
} catch (error) {
res.send(`data error`);
}
}
Results
[{"id":"3cc4ed6e-5974-4661-ade7-ec448ac0e7e3"}]
Problem: I tried to send all data to the backend, but only the UUID was sent. How can I solve this problem