Learn Portuguese (Portugal): O banco pediu um comprovativo de morada.

In Portuguese, comprovativo refers to a specific physical or digital document that proves something, making it a countable noun. You can think of it as a proving document. In English, proof is usually uncountable, but here the bank wants a specific item.

The English translation says asked for. Why is there no word for for after pediu?

The verb pedir inherently means to ask for or to request. Adding a preposition like por after it would be a mistake. You simply use pedir followed directly by the item being requested.

Could I use endereço instead of morada here?

In Portugal, morada is the standard and most natural word for a residential or physical street address. Endereço is understood but is much more commonly used for digital addresses, like an email address (endereço de email) or a web link.

Why is it de morada rather than da morada?

When describing the category or type of an object, Portuguese often drops the definite article. The bank is asking for a general proof of address document (de morada), rather than proof of a specific, previously discussed address (da morada).