We write it as 鯉[koi] in kanji in Japanese.
There is no Kanji for "madsam."
you can't
Earthquake in kanji is written as 地震.
龍 or 竜
'Ojiichan' written with kanji isお祖父ちゃん.
酒 is the Kanji for sake.
尊厳 Songen
you don't its written in katagana
櫻.
The most common form would be 由紀子 You could also write it as 雪子、which is the kanji for snow plus the kanji for child.
you don't its written in kanji 日本語 When you write sentences in Japanese you will use a mixture of Kanji, Hiragana and Katakana.