This is usually in the form of a tripod, but there are other choices. The general rule with tripods is that the heavier it is, the better it will resist camera motion. For steadiness, a ball type head on the top is better, since if the support for your camera is shaped like an L , it offers more chance for movement. But what is on the top of the tripod is a fine point that is not essential - any tripod is better than no tripod. If you have a tripod, it works best if your camera can be activated without you touching it while it takes the picture.
Many cameras can use a cable release.
With a timer, you get the camera steady on a tripod or something else, activate the timer, and stand back. There are other options for tripods. I have taken some nice sharp photographs with a little bracket that I fasten on my car window and a screw mount which fits into the bottom of the camera. Fastened to the window, with the car motor turned off and me being very still, my camera's self-timer allows some very steady photographs. Wildlife and wilderness photographers who do not want to carry a tripod will often use some variation of a bean bag.