I'm by no means a fluent speaker, but I'll try my best to correct this.

Broken down:

こんにちは (corrected your spelling)!　なまえ　は(grammar point wa, uses は)　ダニエル(this is a foreign name, so katakana is to be used)　です (changed to a statement, not a question)。
おげんきですか(added o at the beginning. It's a grammar thing.)？ わたし　は(same thing here)　にほんご　を　わかりません（I assume what you wrote was a less formal version of this. It might have been fine as it was.）。　でも(shikashi might've been fine. Demo should be fine as well though.)　わたし　は(changed わ to は)　べんきょうして　います (changed "i will study" to "i am studying". I believe with "i will study" it should've been べんきょうします)。

So in kana, it would be:
こんにちは!　なまえ　は　ダニエル　です。
おげんきですか？ わたし　は　にほんご　を　わかりません。　でも　わたし　は　べんきょうして　います。

And with Kanji, it's:
こんにちは！名前はダニエルです。
お元気ですか？私は日本語を分かりません。でも私は勉強しています。

Take my corrections with a grain of salt. I'm sure this correction has one or two errors as well.