Balance is the equal distribution of visual weight. Balance can be affected by many things, including color, size, number, and negative space.
Mastering balance can be tricky for beginners because it does take some intuition. Luckily, the design world is full of examples that can help you understand its different iterations.
Symmetrical designs are the same or similar on both sides of an axis. They feel balanced because each side is effectively the same (if not identical).
Asymmetrical designs are different, but the weight is still evenly distributed. The composition is balanced because it calls attention to the right things (in this example, the person’s name and company logo).