Responsive web design is a setup where the server always sends the same HTML code to all devices and CSS is used to alter the rendering of the page on the device. Responsive design serves all devices with the same code that adjusts for screen size.
Google's algorithms should be able to automatically detect this setup if all Googlebot user agents are allowed to crawl the page and its assets (CSS, JavaScript, and images). Know why responsive design is important and Google approved. Read more https://bit.ly/3O4zJgD