Durante a reunião online, eu prefiro usar fones de ouvido.

Because reunião is a feminine noun in Portuguese, so it takes the feminine singular article a.

• a reunião = the meeting
• uma reunião = a meeting

This is something you simply have to learn with the noun. The ending -ão does not automatically mean masculine.

Durante means during and introduces a time expression.

So:

• durante a reunião online = during the online meeting

It is followed by a noun phrase, not a verb. That is why you get:

• durante a reunião
• durante o almoço
• durante a aula

The comma separates the introductory time phrase from the main clause.

• Durante a reunião online, eu prefiro usar fones de ouvido.

This is very natural in writing. In less careful writing, some people may leave the comma out, but using it here is normal and clear.

That is true: Portuguese often drops subject pronouns when the verb already makes the subject clear.

So both of these are possible:

• Eu prefiro usar fones de ouvido.
• Prefiro usar fones de ouvido.

Including eu can add emphasis, contrast, or clarity. In this sentence, eu is perfectly natural, but not required.

Because preferir is used directly with an infinitive, without de.

Correct:

• prefiro usar
• prefiro estudar
• prefiro esperar

Not standard:

• prefiro de usar

This is different from some other Portuguese verbs that do require a preposition.

In this sentence, preferir means to prefer and is followed by an infinitive:

• eu prefiro usar = I prefer to use

If you compare two things, Portuguese often uses preferir X a Y:

• Prefiro café a chá.
• Prefiro usar fones de ouvido a usar o alto-falante.

A useful note: in careful standard Portuguese, preferir already contains the idea of more, so forms like prefiro mais are usually avoided.

Because after prefiro, the action being preferred is expressed with the infinitive.

• prefiro usar
• prefiro ler
• prefiro trabalhar em casa

This is similar to English prefer to use, except Portuguese does not need a separate word like to before the infinitive.

Fones de ouvido is a very common Brazilian Portuguese expression for headphones or earphones, depending on context.

Literally, it is something like:

• fones = phones/headsets/earpieces
• de ouvido = for the ear / of hearing

In everyday Brazilian Portuguese, people also often shorten it to just:

• fones

So all of these may occur:

• fones de ouvido
• os fones
• meus fones

It can mean either, depending on context.

In everyday Brazilian Portuguese, fones de ouvido is a broad term that can refer to:

• earbuds
• earphones
• headphones

If someone wants to be more specific, they might say:

• fone intra-auricular for in-ear types
• headset for a headset with microphone
• fone de ouvido or fones in general conversation

Because the sentence is speaking about them in a general sense, not a specific identified pair.

• eu prefiro usar fones de ouvido = I prefer to use headphones/earphones in general

If you wanted to refer to specific headphones, you could say:

• eu prefiro usar os fones de ouvido
• eu prefiro usar meus fones de ouvido

So both are possible, but the version without the article sounds more general.

Yes. Online is very common in Brazilian Portuguese, especially in technology, work, and school contexts.

So reunião online sounds natural.

You may also hear:

• reunião virtual
• reunião pela internet
• reunião por vídeo

But reunião online is completely normal and modern.

The tricky part is the nasal ending -ão, which is very common in Portuguese.

A rough pronunciation guide:

• reunião ≈ heh-oo-nee-OWN, but with a nasal ending, not a full English own

Important points:

• the r at the beginning in Brazilian Portuguese is often pronounced like an English h
• ni here sounds like nee
• ão is nasal, so air also passes through the nose

If you are practicing, focus especially on making -ão nasal rather than pronouncing it like normal English ow.

Yes. Portuguese allows some flexibility.

Original:

• Durante a reunião online, eu prefiro usar fones de ouvido.

Also possible:

• Eu prefiro usar fones de ouvido durante a reunião online.
• Prefiro usar fones de ouvido durante a reunião online.

These all sound natural. The original version puts the time setting first, which gives it a slightly more organized or descriptive feel.

Yes, but the nuance is a little different.

• Durante a reunião online emphasizes during the course of the meeting.
• Na reunião online means in the online meeting or at the online meeting.

Both can work in many contexts, but durante is more specifically about the time span.

Compare:

• Durante a reunião online, eu prefiro usar fones de ouvido.
• Na reunião online, eu prefiro usar fones de ouvido.

Both are understandable, but durante feels a bit more precise here.

It works in Brazilian Portuguese very naturally. The main phrase fones de ouvido is especially common in Brazil.

In European Portuguese, you may also hear different vocabulary, such as:

• auscultadores for headphones

So the sentence is correct Portuguese in general, but it sounds especially Brazilian because of the word choice.

Yes, in Brazil many people do use headset, especially in work, gaming, or customer-service contexts.

For example:

• Durante a reunião online, eu prefiro usar headset.

That sounds natural in informal modern Brazilian Portuguese. Still, fones de ouvido is a more fully Portuguese expression and works very well in general contexts.