おはよう。

!! (おはようございます in a formal way) わたしのなまえは Sophia です。!!

Hello Sophia! 

Usually, all foreign names and words are written in katakana not in

kanji, but many people do write their name in kanji (which is wrong)

by:

-finding some kanji with the same sounds as their name but i don't

think it's a good idea because every kanji has more than one reading

or sound, so some people might pronounce it differently than the way

they wanted it to be pronouced, and the meaning of their name will be

totally different than their original name and sometimes even weird.

-or by finding kanji corresponding to the meaning of their name but it

will be pronouced differently too. But still some japanese give their

kids foreign names and they write them in kanji, but those are very

special cases.

These are just my thoughts, i hope you can get some help from a native.

Here is your name in katakana:

If you pronounce your name with a short i:  ソフィア

 In case you pronounce it with a long i:  ソフィーア

Best of luck^^