Art lessons allow kids to explore their creativity.

It's well known that Kids usually have a lot of creativity. At school, teachers should encourage the kid's creativity. How could they do it? They should use art lessons. The kid's brain is prepared for receive a lot of stimulations like bright colors, music, etc. When kids receive this kind of stimulations, they start to laugh and they try to do something with their bodies. For example, when they listen some kind of music, they start to dance and they also try to sing...
Also, Kids have a good relationship with their classmates when they are painting. It's a good way for learn how to share things with other Kids. They share their pen colours colour pens (Writing pen colours would refer to the colour of the pen itself, which is illogical. They can share the colour pens, pens which come in different colours), papers, etc. Besides of Besides this, art lessons are good for kids because they can express their feelings. They can draw sad pictures if they have bad mood or they can be happy if they listen a (No need for an article here) to fun music.
So, it's really important to use art activities to improve the kids' life. - This sentence is quite short, I would suggest trying to expand it to a paragraph (Therefore, I believe it is important to...)

*This text is quite good! The only complaint I have is that the work "kid" (and "kids") are considered childish, you should try to avoid them. although they are technically correct, most adults use "child" (and "children") instead. Good luck with your English studies!