Eu preciso fazer a matrícula do meu filho na escola hoje.

Yes — in Brazilian Portuguese, you can very often omit the subject pronoun when it is clear from the verb.

So both of these are natural:

• Eu preciso fazer a matrícula do meu filho na escola hoje.
• Preciso fazer a matrícula do meu filho na escola hoje.

Because preciso already shows I need, the eu is not required.

Including eu can:

• add emphasis
• make the sentence clearer in some contexts
• sound a little more explicit

So if you want a neutral everyday version, Preciso fazer... is very common.

Portuguese often uses a structure like:

• precisar + infinitive

So:

• preciso fazer = I need to do
• literally: I need do / I need to do

This is very similar to English.

Other examples:

• Preciso estudar. = I need to study.
• Preciso sair agora. = I need to leave now.

In your sentence, fazer is used because the expression is fazer a matrícula.

Yes, fazer a matrícula is a very common expression in Brazilian Portuguese.

In this context, it means:

• to enroll
• to register
• to complete enrollment/registration

So fazer a matrícula do meu filho na escola means:

• to enroll my son in school
• or more literally, to do my son’s enrollment at the school

This is a natural phrase in Brazil.

You may also hear:

• matricular meu filho na escola = to enroll my son in school

Both are correct, but fazer a matrícula is extremely common because it focuses on the enrollment process/paperwork.

Portuguese uses articles more often than English does.

Here, a matrícula refers to the enrollment/registration as a specific thing or process.

So Portuguese naturally says:

• fazer a matrícula

not usually just:

• fazer matrícula

This is one of those patterns you get used to. Portuguese often prefers:

• fazer a reserva = make the reservation
• tomar o café da manhã = have breakfast
• pegar o ônibus = take the bus

Even when English might leave out the, Portuguese often keeps the article.

Matrícula can mean different kinds of registration/enrollment, depending on context.

In this sentence, it means:

• school enrollment
• school registration

But in other contexts, matrícula can also mean things like:

• university enrollment
• course registration
• a registration number
• even a license plate in some varieties of Portuguese, though in Brazil placa is more common for that everyday meaning

So context matters. Here, because of na escola, the meaning is clearly school enrollment.

Do is the contraction of:

• de + o = do

In Portuguese, a possessive like meu filho often comes with an article:

• o meu filho

So:

• de + o meu filho → do meu filho

That is why the sentence says:

• a matrícula do meu filho

This structure is very common and very natural.

You may sometimes see de meu filho, but do meu filho is much more standard and common in everyday Brazilian Portuguese.

Na is the contraction of:

• em + a = na

So:

• na escola = in/at the school

Portuguese very often contracts em with articles:

• em + o = no
• em + a = na
• em + os = nos
• em + as = nas

Examples:

• no carro = in the car
• na casa = in the house
• na escola = at/in the school

In your sentence, na escola indicates where the enrollment is being done: at the school.

Good question. Na escola literally corresponds to in/at the school, and Portuguese often uses the same preposition where English might choose different ones.

In this sentence, the full idea is:

• fazer a matrícula do meu filho na escola

That can be understood as:

• doing the enrollment at the school
• enrolling him in the school

The exact English wording depends on how you translate it, but in Portuguese this is perfectly natural.

If you want to make the idea of enrollment into the school even more explicit, you could also say:

• matricular meu filho na escola

Portuguese uses em/na in this kind of context where English often uses in.

Yes. That is normal.

By itself, you can say:

• meu filho

But after certain prepositions, Portuguese often uses the article with possessives:

• do meu filho
• da minha filha
• com o meu amigo
• na minha casa

So the article may appear because the structure requires or strongly favors it.

That means these are both normal:

• Meu filho estuda aqui.
• A professora do meu filho é muito boa.

Yes, hoje can move around.

Your sentence:

• Eu preciso fazer a matrícula do meu filho na escola hoje.

is completely natural.

You could also say:

• Hoje eu preciso fazer a matrícula do meu filho na escola.
• Eu hoje preciso fazer a matrícula do meu filho na escola.
  (possible, but less neutral in many contexts)
• Eu preciso hoje fazer a matrícula do meu filho na escola.

The most common placements are usually:

• at the beginning for emphasis on today
• at the end in a neutral statement

So the original sentence sounds very normal.

Yes. These are both common:

• Eu preciso fazer a matrícula do meu filho na escola hoje.
• Eu tenho que fazer a matrícula do meu filho na escola hoje.

Both mean I need to / I have to.

A very rough nuance:

• preciso can sound a bit like I need to
• tenho que can sound a bit like I have to

But in everyday Brazilian Portuguese, they overlap a lot and both are very common.

Sometimes, but fazer a matrícula or matricular is usually better in this school context.

Most natural options:

• fazer a matrícula do meu filho na escola
• matricular meu filho na escola

Registrar can mean to register, but it is not always the most natural word for school enrollment in Brazil.

So if you are talking about putting a child into a school, stick with:

• matrícula
• matricular

A natural Brazilian pronunciation would sound roughly like:

• Eu preciso fazer a matrícula do meu filho na escola hoje.
• Approximate sound: eh-ooh preh-SEE-zoo fah-ZEHR ah mah-TREE-koo-lah doo meh-ooh FEE-lyoo nah es-KOH-lah OH-zhee

A few useful pronunciation notes:

• preciso: the stress is on -ci- → pre-CI-so
• fazer: the final r is often softer in Brazilian Portuguese
• matrícula: stress on trí → ma-TRÍ-cu-la
• filho: lh sounds like the lli in million for many English speakers
• hoje: the j sounds like the s in measure

You do not need to pronounce every word separately and sharply; in natural speech, the sentence flows together smoothly.

You would change:

• meu filho → minha filha

So the sentence becomes:

• Eu preciso fazer a matrícula da minha filha na escola hoje.

Notice two changes:

1. meu becomes minha because filha is feminine
2. do becomes da because now it is:
   • de + a = da

So:

• a matrícula da minha filha

It is neutral and natural. You can use it in everyday conversation without any problem.

It is not slang, and it is not overly formal either.

You could say it:

• to a friend
• to a school employee
• on the phone
• in a normal conversation

A slightly more formal version might be:

• Preciso realizar a matrícula do meu filho na escola hoje.

But in everyday Brazilian Portuguese, fazer a matrícula sounds very normal and natural.