React + PHP - How to deploy the API files

Hello i created a litle webpage with React and made an PHP API. Everything works on my PC, but i don't understand where i should upload my PHP files. First of all, when i make a call with axios i should put the url of the API, i can't write simple localhost. Example: "http://www.test.com/api/engines.php" Correct? I made different Routes in react with react-router-dom and i don't understand how i should be able to access these PHP files and where to put them. They shouldn't be also private from extern? I want to upload the webpage to test it on cPanel and i got stuck with this litle detail and i can't find any youtube video and chatgpt isn't helping me.