A suit pocket square is a stylish accessory that can elevate a man's formal look.  Some people think that a light pocket square is advised when wearing a dark suit, while others believe a dark pocket square complements a light-colored suit.
You can choose from various patterns, textures, and colors to match your suit and personal style. 
To style your pocket square, you can fold it neatly for a sharp look or puff it for a relaxed vibe. There are also accessories available like pocket square holders to help keep your pocket square in place.