How do I send an email using nodemailer from subdomain as sender's email?

Question

I want to send an email from my subdomain ie contact@mydomain.com which is already set up with my Gmail account. I have written the code for sending mail using nodemailer but it sends an email in the name of my Gmail account name. So, how should I achieve it?

const nodemailer = require("nodemailer");
require("dotenv").config();

exports.newmailer = (email,subject,body)=>{
    return new Promise(async(resolve,reject)=>{
        let transport = nodemailer.createTransport({
            service: 'gmail',
            auth: {
                user: process.env.email,
                pass: process.env.password
            }
        });

        let mailOptions = {
            from: process.env.email,
            to: email,
            subject: subject,
            html: body
        }

        transport.sendMail(mailOptions,(err,data)=>{
            if(err){
                console.log(err);
                return reject(err);
            }
            else{
                let result = "mail sent";
                return resolve(result);
            }
        })
    });
}