you don't its written in katagana
We write it as 鯉[koi] in kanji in Japanese.
There is no Kanji for "madsam."
you can't
龍 or 竜
'Ojiichan' written with kanji isお祖父ちゃん.
jishin 地震
酒 is the Kanji for sake.
尊厳 Songen
you don't its written in katagana
櫻.
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.
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.