The dandelion is a type of flower that is naturally generated in the Overworld. It is one of several different types of flowers in the game. They are used for decoration but are also a vital ingredient for crafting dyes of different colors. They are a non-cultivable plant unlike wheat, sugarcane, etc.
A dandelion flower in a forest (via screenshot)
The dandelion is a flower that is commonly found in forest biomes or plains. They can be broken instantly with any tool or even with your bare hands. You can also harvest them with a pair of shears. Flowers will mostly be generated in random patches on dirt and grass blocks. You have a chance of spawning a flower when using Bone Meal on a grass block.
Dandelion flowers among others in a forest (via screenshot)
Flowers can be used to create suspicious stew. The effects of this stew are different depending on what flower is used. A suspicious stew with a dandelion in it will give the player the saturation effect for 0.35 seconds.
The dandelion is a yellow flower that is primarily used for producing yellow dye, breeding bees, and decorating your builds by placing them in flower pots. It is most commonly found in plains and flower forest biomes.
Making yellow dye from a dandelion (via screenshot)
A. Dandelions can be found in plains or flower forest biomes. They can also be obtained by using Bone Meal on a grass block in any of the above biomes.
A. The dandelion can be turned into yellow dye that can be used to color wool, carpets, etc.