Deployment from localhost to real domain

Hello all,

I hope everyone is doing well.

I have built a subscription based web app, where my subscribers pay a monthly fee to view certain content on my application.

I am using ReactJS, MongoDB and Stripe. Obviously I have built it in development to run on localhost:3000 and the backend to run on port 8000.

My question is, how do I deploy it to work as normal from my own purchased domain, still having access to my MongoDB collections and stuff.

Your help would be much appreciated.