Storing user._id in cookie for later use - node.js

Question

I am writing a application that uses JWTs for user authentication. I am trying to allow the user to submit or edit resources associated ONLY to there ID which is generated when they create their account in MongoDB only after the user has logged in. My instructor suggested to store the user._id within a cookie but not familiar with that process. Any tips on how I could accomplish this?
Here is an example of how my users are registered within the server
app.get('/register', function (req, res) {
res.sendFile(__dirname + '/public/register.html');
});
app.post('/register', async function (req,res) {
try {
req.body.password = await bcrypt.hash(req.body.password, 10);
var newUser = new User(req.body);
newUser.save(function(error,user){
res.redirect('/login');
});
} catch{
res.redirect('/register');
}
// console.log(newUser);
});
Here is the auth process
const JwtStrategy = require('passport-jwt').Strategy;
const ExtractJwt = require('passport-jwt').ExtractJwt;
const bcrypt = require('bcrypt');
const opts = {}
opts.jwtFromRequest = ExtractJwt.fromAuthHeaderAsBearerToken();
opts.secretOrKey = process.env.secret;
module.exports = new JwtStrategy(opts, async (jwt_payload,done)=> {
const user = await (req.body.email);
if( jwt_payload.email === req.body.email){
return done(null, true)
}
try {
if (await bcrypt.compare(password, user.password)){
return done(null, user);
} else {
return done(null, false, { message: "Password is incorrect"});
}
} catch (e) {
return done(e);
}
})
Here is logging in
app.post('/login', async (req, res) => {
const { username, password } = req.body
const user = await User.findOne({ username }).lean()
if (!user) {
return res.sendFile(__dirname + '/public/401.html');
}
if (await bcrypt.compare(password, user.password)) {
// the username, password combination is successful
const token = jwt.sign(
{
id: user._id,
username: user.username
},
process.env.secret
)
console.log(user._id);
//I need to find a way to send over the user._id to the client side so it can be stored later to allow the user to only update their resources and to view their resources
return res.redirect('/welcome.html');
}
res.sendFile(__dirname + '/public/401.html');
})
EDIT: I am not not wanting to store the token unless that is the only way to pass the user._id to the client side due to security reasoning.
Technologies I am using are, Node.js, Express.js, Mongoose, MongoDB, JWT, passport, jwt-simple, bcrypt, methodOverride, and secrets for resetting the users password and creating the user are stored in an .env.