Depends. Some cameras will still "beep" when the focus is right. You'd have to look that up for the camera you have.
You can use live view as well, but it's fiddly.
When cameras were manual focus, they generally had better focussing screens. Often "split screen" where the image appears to be split until in focus. Modern camera focusing screens are generally not as good for focusing, but give a better view.
Really though you're worrying about stuff that there is no need to worry about. If you really are an absolute beginner as it sounds you are, get the camera and learn to take photographs with the kit lens first before worrying about other stuff.