mMy fFavorite hHobby

mMy favorite hobby is drawing .

iI love the colors because it makes me happy , w. When iI draw i switch off, my stress and problems seem like they fade away.

This is my best guess at what you intended to write. Note that "I" is always capitalized.

sSometimes iI love drawing thescenes from nature and s. Sometimes the, I love drawing faces .

This is also my best guess at what you intended to write.

iI started drawing when iI was a child, and now itit eventually becoames an important part of my life.

You could also say "it is now an important part".

mMy favorite hobby is drawing .

iI love the colors because it makes me happy , w. When iI draw i switch off , I feel unstressed and problems -free.

"I switch off stress and problems" is understandable but it definitely sounds a bit unnatural. There are a few different expressions you could use to more naturally express the same idea. For example:

"When I draw, I feel relaxed and carefree."
"When I draw, I feel like I don't have a care in the world."
"When I draw, I feel at peace."

There isn't really one correct way to express the idea.

sSometimes iI love drawing the nature, and sometimes the faces .

iI started drawing when iI was a child, and now it has becomes an important part of my life

mMy fFavorite hHobby

In titles, major words are capitalized.
Otherwise, a lack of capitalization is usually done for stylistic reasons, or when a style guide or publication requires another way of capitalization (such as sentence case, where it's capitalized like it's a sentence).

mMy favorite hobby is drawing .

Capitalize words at the beginning of sentences, and leave no space between words and punctuation that follow them!

iI love the colors because ithey makes me happy ,; when iI draw iI switch off stress and problems .

I is always captitalized, unless it is kept in lowercase for stylistic reasons.
"it" -> "they" because "colors" is plural.
"makes" -> "make" because it follows "they"

It would also be better to specify what colors you are talking about, since there isn't much context for where these colors are coming from. For example "I love the colors of my coloring pencils", or, "I love the colors on the page".

Note: This is assuming that by "the colors", you are referring to actual colors (like red, green, yellow), and not the act of coloring. If you mean to refer to coloring, where you are doing the act of applying color to something, then the sentence would become "I love coloring because it makes me happy".

Word choice: "switch off" could turn into "escape my", "get a break from", "no longer think about" or something similar, depending on what you want to mean.

sSometimes iI love drawing the nature and sometimes theI love drawing faces .

"Sometimes I draw nature and sometimes I draw faces." might be better. The current sentence implies that your love for drawing nature or faces, is only sometimes. But what I think you might mean here, is that you love drawing, and that you sometimes draw nature and sometimes draw faces.

iI started drawing when iI was a child, and now itit has becomes an important part of my life.

"start" -> "started" because you started in the past (when you were a child) and so the action "to start" should be in past tense.

If you want to say that it became an important part of your life already, the ending should be "and it has become an important part of my life (by now)."
If you want to say that it is currently becoming an important part of your life, the ending should be "and it is becoming an important part of my life."

Sentences typically end with a period, exclamation mark, or question mark.