i need it but i dont know how and where to find it

Forest Sunlight - if you have any, they will be under the Jewel tab in the seed shop.
Enchanted Forest Sunlight - if you have any, they will be under the Enchanted tab in the seed shop.

i dont have it

If you don't have any Enchanted seeds, that tab doesn't show up.

Which is it that you need - Forest or Enchanted?  Lots of average wildlife drop the Forest jewel.

'Forest Sunlight'

They are dropped by all "average" wildlife with names that begin with N - Z (the ones which begin with A - M drop Forest Ambers).  So things like Nivea The Beautiful Fairy, Oriole, Otter, Pair of Lovebirds, Peace Dove, Pink Elephant, Platypus, Puffin, all types of Pygmy Mouse, Raccoon, Rainbow Dragon, Reindeer, Roadrunner, Sea Lion, Seal, Singing Bush Lark
  Skunk. Snowy Owl, Sugar Glider, Viridia The Garden Fairy, Walrus, Wren, Yellow baby chick (gives 3 sunlights), Yellow Wagtail.  Red, Orange, Yellow, Violet and Rainbow candy critters drop them too.