First of all fitness improves energy and give you a healthy body and brain at the same time. It improves your mood and mental health as well. Moving your body makes you feel more strong and more happy. It can as well improve your confidence because you work on your dream body and you feel way batter with yourself and body. For me for example from the time I started working on my body I feel way more happier and better with myself

It helps you have more energy in general as well even if you move your body for 30 minutes everyday It helps a lot with your health, mental health and too many other things

Fitness does not mean just going to gym. You can do any kind of sport that you like and makes you feel better. The point is to move your body and do something.