Para visitar o apartamento, preciso preencher um formulário agora.

Para + infinitive is a very common way to express purpose in Portuguese.

So para visitar o apartamento means in order to visit the apartment or to visit the apartment.

It works much like English:

• Para estudar, preciso de silêncio. = To study, I need silence.
• Para entrar, precisa mostrar o documento. = To enter, you need to show the document.

In this sentence, it tells you why the form needs to be filled out.

Because precisar works in two common patterns:

• precisar + infinitive = to need to do something
  
  • Preciso preencher = I need to fill out
• precisar de + noun = to need something
  
  • Preciso de ajuda = I need help

So here, since the next word is the verb preencher, the correct structure is preciso preencher.

Portuguese often omits the subject pronoun when the verb ending already makes it clear who the subject is.

• preciso already means I need
• so eu preciso and preciso are both correct

In everyday Portuguese, dropping eu is very common unless the speaker wants emphasis or contrast.

For example:

• Preciso preencher um formulário. = I need to fill out a form.
• Eu preciso preencher um formulário, mas ele não precisa. = I need to fill out a form, but he doesn’t.

Preencher means to fill in or to fill out, especially for:

• forms
• documents
• applications
• blanks in a text

So preencher um formulário is the normal way to say fill out a form in Portuguese.

You may also hear completar in some contexts, but preencher is the most natural choice for forms.

Portuguese uses definite articles much more often than English.

So o apartamento literally means the apartment, but in Portuguese this can sound natural even in places where English might omit the.

In many situations, Portuguese prefers:

• visitar o apartamento instead of just
• visitar apartamento

Without the article, it would usually sound less natural here.

Because Portuguese usually uses an article with countable singular nouns when talking about one unspecified item.

So:

• um formulário = a form

If you said only preencher formulário, it would sound incomplete or unnatural in standard Portuguese.

This is similar to English, where you usually say fill out a form, not just fill out form.

They are infinitives because of the structures around them:

• para visitar: after para, Portuguese normally uses the infinitive to express purpose
• preciso preencher: after precisar, the next verb also stays in the infinitive

So:

• para visitar = to visit
• preciso preencher = I need to fill out

This is very normal in Portuguese verb combinations.

Agora often goes at the end, but Portuguese word order is fairly flexible.

These are all possible, though they may sound slightly different in emphasis:

• Preciso preencher um formulário agora.
• Agora preciso preencher um formulário.
• Preciso agora preencher um formulário.
  This one is less common in everyday speech.

The version in your sentence is very natural. Putting agora at the end often sounds neutral and smooth.

Pra is a very common spoken contraction of para in Brazilian Portuguese.

So in conversation, many Brazilians would say:

• Pra visitar o apartamento, preciso preencher um formulário agora.

But in writing, especially careful or formal writing, para is preferred.

So:

• para = full form, standard, good for writing
• pra = very common in speech, informal writing, messages, etc.

Yes. Both are common, but they are a little different in tone.

• Preciso preencher um formulário = I need to fill out a form
• Tenho que preencher um formulário = I have to fill out a form

In many situations, they are interchangeable.
But often:

• preciso can sound a bit more like a need or requirement
• tenho que can sound a bit more direct, like an obligation

Both are natural in Brazilian Portuguese.

Yes. The accent mark matters because it shows the stressed syllable.

Formulário is stressed on lá:

• for-mu-LÁ-ri-o

Without the accent, the word would not follow normal spelling expectations and would be considered incorrect.

Accent marks in Portuguese are important for:

• pronunciation
• stress
• sometimes meaning

A simple Brazilian Portuguese approximation:

• preencher ≈ pree-en-SHER
• formulário ≈ for-moo-LAH-ree-oh
• apartamento ≈ a-par-ta-MEN-too
• agora ≈ a-GO-ra

A few pronunciation notes:

• nh in preencher is like the ny sound in canyon
• lh in formulário does not appear here, so that word is fairly straightforward
• the final r in Brazilian Portuguese can sound softer or more like an h, depending on region

It sounds neutral and natural.

It is appropriate for:

• everyday conversation
• speaking to a receptionist or agent
• normal written communication

It is not overly formal, but it is also not slangy.

If you wanted it to sound more conversational in Brazil, you might hear:

• Pra visitar o apartamento, preciso preencher um formulário agora.

But the original sentence is perfectly standard and natural.