for help

I'll help you by correcting these sentences. The first one: "I am coming from Japan". If you write it like that it sounds as if you are leaving Japan and coming to some other place. I think you meant that you live in Japan and therefore the first sentence should be: "I come from Japan"

The second should be: "I want to study English."

Now, the whole thing would have sounded better if you had written something like this:

"Hello, I'm from Japan and I would very much like to imrove my English. Is there anyone that could help me?"

I'll give you one more advice. Do not use popular chatting vocabularly when you're not that experienced with English. For example: say "you" instead of "u".

Have a great day.

Cheers!