Formal:
* Como vai? (pronounced "koh-moh vye") - This is the most common and polite way to ask someone how they are.
* Como está? (pronounced "koh-moh eh-stah") - This is a slightly more formal version of "Como vai?" and is often used in more formal settings.
Informal:
* E aí? (pronounced "eh-ee") - This is a very casual and informal way to say "how are you" and is often used with friends and family.
* Tudo bem? (pronounced "too-doo bem") - This means "everything okay?" and is a more casual way to ask how someone is.
* Como você está? (pronounced "koh-moh vo-seh eh-stah") - This is a less formal way to ask how someone is, but is still polite.
* Tudo sussa? (pronounced "too-doo soo-sah") - This is a very informal and slang way to ask how someone is and means "everything chill?"
Responding:
* Bem, obrigado/a. (pronounced "bem oh-bree-gah-doh/ah") - This means "well, thank you" and is a polite way to respond to someone who asks you how you are.
* Estou bem, obrigado/a. (pronounced "eh-stoh bem oh-bree-gah-doh/ah") - This means "I'm well, thank you" and is a more formal way to respond.
* Tudo bem. (pronounced "too-doo bem") - This means "everything okay" and is a casual way to respond.
* De boa. (pronounced "deh bo-ah") - This means "chill" or "relaxed" and is a very casual way to respond.
Remember that the best way to say "how are you" in Brazilian Portuguese depends on the context of the situation and your relationship with the person you are talking to.