deploy REST API Spring Boot Application

I'm learning to build a REST API server with java Spring boot(backend), React JS application (frontend), and My SQL DataBase. Everything is working perfectly in the local system.

I want to deploy my application to could that make it available online. that means:

1- Database service to deploy My SQL DB and the server can access the DB.

2- deploy and run Java server (Spring boot) in the cloud and how the client-side (React js)can connect to the server (IP address? etc or what?).

3- also the deploy frontend and get a web domain.

what is the best platform to do that? the easiest, and cheapest.

what I should learn to do that? and what are the process steps?