React cares exactly zero about styling. Think of it as generating the barebones HTML. React will put elements on the page, but everything after that is the job of CSS: how they appear, what they look like, how they’re positioned, and how centered or uncentered they are.
“How to center a div in React” is… not a React problem. It’s a CSS problem. You don’t need “react” in your Google query. Once you figure it out, use React to apply the right CSS class name to your components
How do you center a
<div> in WordPress? How do you center a
<div> in Vue? On one hand, they are broken questions. Those technologies don’t have anything to do with centering things. Centering on the web is something CSS does. On the other hand, higher-level tech is sometimes involved. Maybe there is some Gutenberg thing in WordPress that handles centering on this particular site that you should use for editorial consistency. Maybe there is some styling library being used which means you can’t write regular CSS — you have to write the way the library wants you to write it. Complicated, all this “making websites” stuff.