Formal:
* Adeus: This is the most formal way to say goodbye, similar to "farewell" in English.
* Até logo: This literally means "until soon," and is a polite and common way to say goodbye.
* Até mais tarde: This means "until later," and is also a polite and common way to say goodbye.
Informal:
* Tchau: This is the most common informal way to say goodbye, similar to "bye" in English.
* Falou: This literally means "spoke," and is a slangy way to say goodbye, often used by friends and family.
* Valeu: This means "thanks" or "cheers," and is a more casual way to say goodbye, often used with friends and family.
* Até: This means "until," and is a short and informal way to say goodbye.
Other options:
* Até breve: This means "see you soon," and is a more hopeful way to say goodbye.
* Até já: This means "see you soon," and is a very common way to say goodbye to friends and family.
* Bom dia: This means "good day," and can be used to say goodbye in the morning.
* Boa tarde: This means "good afternoon," and can be used to say goodbye in the afternoon.
* Boa noite: This means "good night," and can be used to say goodbye in the evening.
The best way to choose the right phrase depends on the context and your relationship with the person you're saying goodbye to.