Precisa-se de cópia e de comprovante para fazer o cadastro.

No. Here se is not reflexive.

In this sentence, precisa-se is an impersonal construction. It means something like:

• one needs
• it is necessary to have
• people need

So Precisa-se de cópia e de comprovante... is a formal, bureaucratic way to say that those documents are required.

A more personal version would be:

• Você precisa de cópia e de comprovante...

But the original sounds more neutral and official.

Because this is an impersonal se construction, and with precisar de, the verb normally stays in the 3rd person singular.

That happens because precisar in the sense of to need takes the preposition de:

• precisar de algo = to need something

Since cópia and comprovante come after de, they are not the grammatical subject of the verb. So the sentence does not work like a passive such as Vendem-se casas.

That is why:

• Precisa-se de cópia... is standard
• not Precisam-se de cópia...

Because the verb precisar, when it means to need, is usually used with de:

• precisar de um documento
• precisar de ajuda
• precisar de dinheiro

So:

• Precisa-se de cópia
• literally: One needs a copy

This is just part of how the verb works in Portuguese.

Yes, the repetition is normal, especially in formal or official language.

The sentence repeats de before both items:

• de cópia e de comprovante

This sounds clear and organized, which is very common in notices, instructions, and bureaucracy.

You may also hear or see:

• de cópia e comprovante

That can sound natural too, especially in less formal contexts. But repeating the preposition is very common when listing required items.

Because the sentence is talking about the documents in a general, unspecified way.

In official or bureaucratic Portuguese, articles are often omitted to sound concise:

• de cópia
• de comprovante

This gives the idea of a copy and some kind of supporting document/proof, without emphasizing exact quantity or identity.

If the speaker wanted to be more explicit, they could say:

• de uma cópia e de um comprovante

That is also possible, but the original is more compact and administrative in tone.

Comprovante usually means a document that proves something.

Depending on the context, it can mean things like:

• a receipt
• a proof of payment
• a supporting document
• a proof of address
• some other document used as evidence

In everyday Brazilian Portuguese, comprovante often appears in expressions like:

• comprovante de residência = proof of address
• comprovante de pagamento = proof of payment

So in this sentence, comprovante means some kind of required proof/document, even if the exact type is not spelled out.

Fazer o cadastro means something like:

• to register
• to complete the registration
• to fill out/create the registration record
• to sign up

In Brazilian Portuguese, cadastro is a very common word in administrative, commercial, and online contexts. It can refer to:

• creating an account
• registering in a system
• entering your personal information into a database

So para fazer o cadastro means in order to complete the registration/sign-up process.

Yes, absolutely.

These are both natural, but they are slightly different in tone:

• para fazer o cadastro sounds more bureaucratic or process-focused
• para se cadastrar sounds a bit more direct and personal

For example:

• Precisa-se de cópia e de comprovante para fazer o cadastro.
• Você precisa de cópia e comprovante para se cadastrar.

Both are fine. The original just sounds more like official written language.

Because in standard written Portuguese, object or particle pronouns like se are often attached to the verb with a hyphen when they come after it.

So:

• precisa-se

This is called enclisis.

In formal writing, that hyphen is important. In everyday digital writing, people sometimes make mistakes with it, but the standard form is:

• Precisa-se

Yes. It sounds quite formal, impersonal, and bureaucratic, which is very common in Brazil for signs, instructions, websites, and office language.

A more conversational version might be:

• Você precisa de uma cópia e de um comprovante para fazer o cadastro.
• Pra fazer o cadastro, você precisa de cópia e comprovante.
• Pra se cadastrar, precisa de cópia e comprovante.

The original sentence is the kind of thing you might see on:

• a reception desk
• an application form
• a clinic or school notice
• a government or bank website