Formal:
* Divirta-se: This is the most formal way to say it.
* Desfrute: This translates to "Enjoy yourself," which is a more formal way of saying "Have fun."
Informal:
* Se divirta: This is the most common and informal way to say "Have fun."
* Aproveite: This means "Make the most of it" or "Enjoy yourself" and is a bit more informal than "Divirta-se."
* Se joga: This is a very casual and slangy way to say "Have fun" and literally translates to "Throw yourself in."
Other options:
* Boa diversão: This is a literal translation of "Have fun" and is often used in situations where you want to be more specific about the fun you wish them to have.
* Que você se divirta muito: This translates to "I hope you have a lot of fun" and is a more expressive way to say it.
The best choice depends on the situation. If you're talking to someone you don't know well, it's best to use a formal expression like "Divirta-se." If you're talking to a friend or family member, you can use a more informal expression like "Se divirta."