Preciso anexar o comprovante antes de enviar a resposta.

Portuguese often leaves out subject pronouns when the verb form already makes the subject clear.

Here, preciso is the 1st person singular form of precisar, so it already means I need. Because of that, Eu preciso anexar... and Preciso anexar... both mean the same thing.

In Brazilian Portuguese, leaving out eu is very natural unless you want emphasis or contrast.

Here, preciso is a verb, from precisar = to need.

So:

• Preciso anexar... = I need to attach...

But preciso can also be an adjective meaning precise / accurate:

• O relatório está preciso. = The report is precise.

In your sentence, because it is followed by anexar, it is clearly the verb.

Because after precisar, Portuguese normally uses an infinitive.

So the structure is:

• precisar + infinitive
• Preciso anexar... = I need to attach...

This is similar to English need to + verb, except Portuguese does not use a separate word like to before the second verb in the same way. The infinitive itself is anexar.

Comprovante is a very common Brazilian Portuguese word for a document that proves something.

Depending on context, it can mean:

• receipt
• proof
• confirmation slip
• supporting document

For example, it could be a payment receipt, bank proof, registration confirmation, or some other official document. It is broader than just receipt.

Portuguese uses definite articles very often, more often than English does.

So:

• o comprovante = the receipt / the proof document
• a resposta = the response / the answer

In English, you might sometimes leave out the, depending on the situation, but in Portuguese the article often sounds more natural, especially when the speaker has a specific document or response in mind.

Also, the articles match the gender of the nouns:

• comprovante is masculine → o
• resposta is feminine → a

After antes, Portuguese normally uses de before an infinitive.

So the pattern is:

• antes de + infinitive

Examples:

• antes de sair = before leaving
• antes de pagar = before paying
• antes de enviar = before sending

So antes de enviar a resposta means before sending the response.

The default understanding is that it is the same person as the subject of preciso.

So:

• Preciso anexar o comprovante antes de enviar a resposta.
• natural meaning: I need to attach the document before I send the response.

Portuguese often uses the infinitive this way when the subject stays the same.

If you wanted to make the subject explicit, you could say something like:

• antes de eu enviar a resposta

But in everyday Portuguese, that is often unnecessary when the meaning is already clear.

That part is simply understood from context.

In real life, this sentence usually appears in situations involving:

• an email
• an online form
• a message
• a ticket or request system

So anexar o comprovante means attach the proof document, and Portuguese does not always repeat to the email or to the reply if it is obvious.

English does this too sometimes, but Portuguese is especially comfortable leaving that detail unstated.

Yes. Anexar is very common in Brazilian Portuguese, especially in formal or semi-formal contexts such as:

• emails
• online forms
• customer support messages
• administrative or business writing

Examples:

• Vou anexar o arquivo. = I’ll attach the file.
• Por favor, anexe o comprovante. = Please attach the proof document.

It is one of the most normal verbs to use for files and documents.

Portuguese often uses the definite article where English might prefer a possessive, especially when ownership is obvious from context.

So enviar a resposta can naturally mean:

• send the response
• send my response

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

• enviar minha resposta
• enviar a minha resposta

But in many everyday situations, a resposta sounds completely natural and is enough.

Yes. Resposta can mean either answer or response, depending on context.

For example:

• if someone asks a question, resposta may be answer
• if you are replying to an email or form, resposta may be response or reply

In this sentence, response/reply is probably the most natural interpretation because of the context with anexar o comprovante and enviar.