Formal:
* До свидания (Do svidaniya) - This is the most common and formal way to say goodbye. It literally translates to "until we meet again."
* Прощайте (Proshchayte) - This is a more formal and less common way to say goodbye, usually used for a final farewell.
Informal:
* Пока (Poka) - This is the most common informal way to say goodbye, similar to "bye" in English.
* До встречи (Do vstrechi) - This means "until we meet" and is slightly more formal than "Пока."
* Всего хорошего (Vsego khoroshego) - This means "all the best" and is a polite way to say goodbye.
* Спокойной ночи (Spokoynoy nochi) - This means "good night" and is used when departing in the evening.
Other options:
* Удачи (Udachi) - This means "good luck" and is a casual way to say goodbye.
* Счастливо (Schastlivo) - This means "happily" and is another casual way to say goodbye.
The best way to say goodbye in Russian depends on the situation and your relationship with the person you are speaking to.