こんいちわ！

red is a wrong word.

bold is correct word.

blue is same meaning and another words.

こん（い）にちわ！

こん（い）にちわ！わたしはmelissaです。英語ははな（し）せます。ちょっと日本語（が）をはな（し）せます。日本語はむずかしいです。わたしのねこはしろいろ（しろ）とはいいろ。 (That's a little irrelevant. I can't think of anything else to say!)
My Japanese is rusty. Sorry!

Nice to meet you, Melissa.

I want to show your cats's picture.