There's no capitalization in written Chinese.

But there is a "upper case" for writing numbers. Its set of very complex characters meant for writing contracts so you can't easily tamper with it.

Like "一" (one) could be easily changed to a "十" (ten) with just one stroke, but "壹" also means "one", but you can't add strokes to change it, any attempt at tampering with contracts/documents would be easily noticed. Usually this is never used in every-day life.

(Wikipedia https://en.wikipedia.org/wiki/Chinese_numerals#Ordinary_numerals)

It's not really "capitalization" but more like writing "One Thousand Dollars" instead of "$1000"

Idk what you mean by "emphasis", but there is no difference between proper nouns and common nouns. I mean, there is italics and bold if written digitally. Or underlining it if written on paper.

(I'm Chinese-American btw)