Breaking a single line Chinese sentence into multiple lines for design purpose
In terms of grammar, Chinese also uses punctuation marks to delimit fragments and sentences, so a line break usually doesn't indicate a new sentence. The only hard rule is that most punctuation marks should not begin lines. Most word processing software should enforce this for you.
After this it's a stylistic question. It's true in Chinese, just as it is in English, that line breaks introduces a pause. It's an effect that poetry often takes advantage of. Usually it's bad to pause in the middle of a word, and since Chinese words are made up of one to many characters, you need someone that understands Chinese to identify the words and avoid breaking them. In your example sentence, they are:

用户 - 的 - 肌肤 - 变得 - 更 - 亮白

Line breaks emphasise the first word of a line, so maybe you want to do it to emphasise certain words. This emphasises the &quot;becomes&quot;:

用户的肌肤
变得更亮白

This emphasises the &quot;more&quot;

用户的肌肤变得
更亮白

Or you can really overdo the line breaks and make it seem like shouting

用户的肌肤变得
更!
亮!
白!

But really, these are all design decisions, which don't occur in a vacuum. You need to go back to your client and ask what they would like. Maybe they value the shape of the text, even if it means breaking in the middle of a word. Maybe they don't want line breaks at all, even if the text must be resized. Maybe they just don't care.