Formal:
* Bem-vindo(a) - This is the most common and formal way to say "welcome" in Portuguese. You would use this for a person or group, for example, "Bem-vindo(a) ao nosso hotel" (Welcome to our hotel).
Informal:
* Seja bem-vindo(a) - This is a slightly more formal way to say "welcome," but it's still commonly used.
* Bem-vindos(as) - This is the plural form of "bem-vindo(a)" and is used when welcoming multiple people.
* Seja(m) bem-vindo(s) - This is the plural form of "seja bem-vindo(a)" and is used when welcoming multiple people.
* Bem-vindo(a) de volta - This means "welcome back" and is used when someone returns after being away.
Other:
* Boas-vindas - This means "welcome" and is often used as a greeting or in a more formal setting, such as a welcome message on a website.
* Bem-vindo(a) à nossa casa - This literally means "Welcome to our home" and is a warm and welcoming phrase.
The best translation for "welcome" will depend on the context and the level of formality you are going for.