Learn Portuguese (Portugal): Temos de enviar o passaporte ao cliente. - We have to send the passport to the client.

The verb ter usually means "to have" (like owning something). But when you put de between a form of ter and an action verb in its basic, unaltered form (like enviar, meaning "to send"), it creates a rule: ter de means "to have to" or "must". So, temos de enviar translates to "we have to send".

Where is the word for "we" in this sentence?

Since temos is specifically the "we" form of the verb ter, the subject is already obvious from the verb itself. You could say Nós temos de enviar, but Portuguese speakers usually drop the nós (we) to sound more natural.

Why is it ao cliente instead of a o cliente to mean "to the client"?

In Portuguese, you cannot leave the preposition a (to) and the definite article o (the) sitting next to each other. They must merge into a single combined word: the contraction ao (to the).

Would the word cliente change if the client was a woman?