Title says it all 
For students, they use Pinyin or another pronunciation system. (But Pinyin is the standard on mainland China at least.)
Otherwise, pronunciation clues are given in the characters themselves via the use of various radicals. For example, the radicals for “female” and “horse” make up the character for “mother.” The horse provides the pronunciation clue. This is more of an art than a science.
To expound on Freido’s summary.
The more traditional Chinese dictionaries for adults are all characters. You’re expected to either know how to pronounce the character already or to be able to figure it out from the radical. (Radical is a building block that characters are made out of.)
Kids and more modern style dictionaries use a romanization system (of which pinyin is the most popular) or zhuyin fuhao (which is a list of symbols that purely represent sound - like the Japanese katakana system).
Electronic dictionaries will “speak” the words.
There’s a system of 37 pronunciation characters commonly called the Bopomofo system (named after the first 4 characters) that tells you how to pronounce something. Each word has 1-3 characters forming a single syllable sound and has one of 4 tonal marks to indicate how that word is said aloud. Its not a great system
So none of them use the International Phonetic Alphabet?
The IPA won’t generally be used for any reference works aimed students or laymen. In scholarly works, yes.
I have an elementary Chinese language book for students, published in the People’s Republic. It uses IPA.
That’s interesting. If it was a book for high-schoolers or college students (“elementary” perhaps meaning "elementary material for second-language learners), than it makes sense.
If it was truly a resource for elementary-school age children, then I am surprised. But, hey, ignorance fought.
Does IPA use tone marks? The tone is essential to Chinese pronunciation.
Yes, the IPA has tone marks.
College students generally know IPA, and use it to learn foreign languages. My Chinese college students were always coming to me asking for pronunciation help, and they were horrified when I said I never learned IPA. I’ve never seen it used for Chinese pronunciation, but I’m sure it happens sometimes.
The vast majority of stuff intended for kids is in Pinyin, and that is what the school systems use.
I meant not that it was for elementary school. It was for college level Chinese 101. Pinyin was the transcription used, naturally, but the phonemes themselves were introduced using IPA.