Learn Italian: Ognuno fa ciò che vuole. - Everyone does what they want.

Just like "everyone" in English, the Italian pronoun ognuno is grammatically singular. Because of this, it always takes a third-person singular verb. This is why we use fa and vuole instead of their plural forms (fanno and vogliono).

Could I use ciascuno instead of ognuno in this sentence?

Yes, you could say Ciascuno fa ciò che vuole. Both words can mean "everyone" or "each one." However, ognuno tends to emphasize the whole group as a collective, while ciascuno puts a little more focus on the individuals within the group. In this context, they are perfectly interchangeable.

What does ciò che mean here, and could I use something else instead?

Ciò che translates to "that which" or "what" (when "what" is a statement, not a question). It connects the two halves of the sentence. You can also use quello che here. Saying ognuno fa quello che vuole means the exact same thing, though ciò che sounds slightly more formal and elegant.

The English translation says "what they want", but vuole is strictly singular. Why the difference?

In English, we often use the singular "they" to refer to an unspecified person, especially after words like "everyone". In Italian, ognuno strictly requires the third-person singular form. So vuole literally means "he or she wants", keeping the Italian grammar consistently singular throughout the entire sentence.