When you were a baby, your voice and all the supporting muscles were working perfectly. You had no posture problems, so your head was aligned properly with your shoulders and spine, your diaphragm was working properly, gratefully accepting help from your abdominal muscles to support the enormous sound you could make. You could wail like a gospel singer and not hurt anything. How can this be when you never had lessons?
Those of us who were constantly singing as children and never stopped as we grew older tend to keep this natural ability. Even then, sometimes it diminishes because we continue singing through life in a style that doesn't need the support of the big voice, but we do keep it in a lesser way. (This was the case with me, so I did have to sort of relearn it.)
Then there are those of us who, although we have beautiful voices and lots of talent, did not constantly sing as children, having other things to do, and for those this natural ability becomes so distant that it is no longer even a memory.
So we need to wake up that memory. It's not difficult really. In fact, some of the voice exercises that are commonly used in training methods are exercises like the "baby cry" or the "twang" sound, both of which bring us back to our born abilities.