Snowflakes are formed in the clouds above us. Because it is high in the sky, the temperature is very low, and the snow is initially formed as small icicles in the cold sky. Because of the cold air around it, water vapor in the air gradually adheres to these ice cubes, creating snow of various shapes. There are so many different shapes, such as a square plate, a pillar, a pistol ball, a flower with six petals, and so on.
The shape of the snow is determined by the temperature and the moisture content of the air at any given time. For example, snow that passes through an area with a lot of water vapor will look like six petals, while snow that passes through an area with little water vapor and low temperature will look like an angular column.
As you can see, there are many different shapes of snow, but all snow is still made of water-cooled ice.