O remetente escreveu o código postal.

Remetente means sender.

It is a noun that is often treated as common gender, which means the form remetente can refer to either a man or a woman. The article tells you the gender in the sentence:

• o remetente = the sender (male, or masculine reference)
• a remetente = the sender (female)

So in your sentence, o remetente is masculine because of the article o, not because the noun itself changes.

O is the definite article the for a masculine singular noun.

Here it goes with remetente:

• o remetente = the sender

Portuguese uses articles very often, sometimes more often than English does. In a simple sentence like this, using o is completely natural.

Escreveu is the pretérito perfeito do indicativo, which corresponds to the simple past in English in many cases.

It comes from the verb escrever = to write.

Conjugation:

• eu escrevi = I wrote
• tu escreveste = you wrote
• ele/ela/você escreveu = he/she/you wrote
• nós escrevemos = we wrote
• vós escrevestes = you all wrote
• eles/elas/vocês escreveram = they/you all wrote

So o remetente escreveu = the sender wrote.

Because escreveu is a conjugated verb, while escrito is the past participle.

• escreveu = wrote
• escrito = written

Examples:

• O remetente escreveu o código postal. = The sender wrote the postal code.
• O código postal foi escrito pelo remetente. = The postal code was written by the sender.

So in your sentence, you need the main past-tense verb, which is escreveu.

That o is also the definite article the, this time for código, which is a masculine singular noun.

• o código postal = the postal code

In Portuguese, the article normally comes before the whole noun phrase, not before every word in it. So:

• o código postal not
• o código o postal

The noun phrase is built like this:

• código = code
• postal = postal
• o código postal = the postal code

In Portuguese, adjectives often come after the noun.

So:

• código postal = postal code

This is very normal in Portuguese. English often puts descriptive words before the noun, but Portuguese frequently places them after it.

Other examples:

• cor azul = blue colour
• serviço público = public service
• endereço eletrónico = email address / electronic address

So código postal follows a very common Portuguese pattern.

Yes. In European Portuguese, código postal is the standard term for postal code / postcode.

A useful cultural note:

• In British English, learners may naturally think of postcode
• In American English, they may think of ZIP code
• In Portugal, the normal term is código postal

So this is exactly the expression you would expect in Portuguese from Portugal.

Yes, this sentence follows the basic Subject + Verb + Object order:

• O remetente = subject
• escreveu = verb
• o código postal = direct object

So the structure is very straightforward:

• The sender / wrote / the postal code

This makes it a good beginner sentence, because the syntax is very similar to English.

Not if you want the same meaning.

• escreveu o código postal = wrote the postal code
• escreveu no código postal would suggest something like wrote on the postal code, which sounds odd in most contexts

With escrever, if you mean writing some words or numbers, you usually use it directly with the thing written:

• escrever o nome = write the name
• escrever a morada = write the address
• escrever o código postal = write the postal code

So in your sentence, no preposition is needed.

In European Portuguese, escreveu is pronounced approximately like esh-kreh-VEU, though the exact sounds are not identical to English.

A rough breakdown:

• es often sounds like esh
• cre sounds roughly like kreh
• veu sounds a bit like veu with stress on this last part

The stress is on the final syllable:

• es-cre-veu

This is typical of many past-tense forms in Portuguese.

The accent mark in código shows the stressed syllable.

• código is stressed on có
• So it is pronounced roughly CO-di-go

Without the accent, Portuguese stress rules would lead you to expect a different stress pattern. The written accent helps show the correct pronunciation.

This is important because stress is a regular and meaningful part of Portuguese spelling.

Yes. You could replace it with ele or ela if the context is clear:

• Ele escreveu o código postal. = He wrote the postal code.
• Ela escreveu o código postal. = She wrote the postal code.

You could also use você if you mean you in a formal or neutral way:

• Você escreveu o código postal.

But in the original sentence, o remetente is more specific because it identifies the person by role: the sender.

Yes, it is grammatically natural and easy to understand.

That said, in real-life situations, Portuguese speakers might also use related words depending on context, such as:

• morada = address
• destinatário = recipient
• envelope = envelope

But O remetente escreveu o código postal. is a perfectly normal sentence for practice and for understanding basic grammar and vocabulary.