Formal:
* 再见 (zàijiàn): This is the most common and versatile way to say goodbye. It literally means "see you again."
* 告辞 (gàocí): This is a more formal way to say goodbye, often used in business or official settings.
Informal:
* 拜拜 (bàibai): This is a casual and friendly way to say goodbye.
* 88 (bā bā): This is a very informal slang expression for goodbye, similar to "later" in English.
Other options:
* 慢走 (mànzǒu): This literally means "walk slowly" and is used when someone is leaving on a journey.
* 一路平安 (yīlù píng'ān): This means "safe travels" and is a more formal way to wish someone well as they leave.
The best way to choose which one to use depends on the situation and your relationship with the person you are saying goodbye to.