Senha vs. palavra-passe
While both words translate to "password", the choice depends largely on regional variance between Brazilian and European Portuguese, as well as specific contexts regarding waiting lines.
Senha
A1This is the standard word for "password" in Brazilian Portuguese for all digital contexts. However, in both Brazil and Portugal, senha also refers to a physical ticket or number you take while waiting for your turn in a queue (like at a bank or bakery).
Você pode me passar a senha do Wi-Fi?
(Can you give me the Wi-Fi password?)
Por favor, retire uma senha e aguarde ser chamado.
(Please take a ticket and wait to be called.)
Eu esqueci a minha senha do banco.
(I forgot my bank password.)
Palavra-passe
A1This term is used primarily in European Portuguese (Portugal) to refer to a secret code for accessing systems or accounts. It literally translates to "pass-word". While password (the English word) is also frequently used in Portugal, palavra-passe is the formal Portuguese term there.
Introduza a sua palavra-passe para continuar.
(Enter your password to continue.)
A sua palavra-passe expirou, por favor crie uma nova.
(Your password has expired, please create a new one.)
Nunca partilhe a sua palavra-passe com ninguém.
(Never share your password with anyone.)
Summary
Use senha if you are speaking Brazilian Portuguese or if you are referring to a queue number/ticket in any region. Use palavra-passe if you are speaking European Portuguese and referring to a login code.