Arquivamos a nota fiscal eletrônica, pois o documento é importante.

Arquivamos is the 1st person plural form of arquivar, so the subject is we.

Portuguese often leaves the subject pronoun out, so instead of saying nós arquivamos, it is very natural to say just arquivamos. The verb ending already shows who is doing the action.

In Brazilian Portuguese, arquivamos can be either:

• present indicative: we archive / we file
• preterite: we archived / we filed

For many -ar verbs, the nós form looks the same in these two tenses. So learners usually have to rely on context to know which one is meant.

A useful extra note: in European Portuguese, the preterite is often written arquivámos, which makes the difference visible in writing. In Brazilian Portuguese, both are normally written arquivamos.

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

So a nota fiscal eletrônica means the electronic invoice / the electronic tax invoice and sounds natural when referring to a specific document. Even in places where English might sound okay without the, Portuguese often still prefers the article.

Because nota is the main noun, and it is feminine singular.

So:

• nota → feminine singular
• eletrônica → feminine singular to agree with nota

But fiscal is an adjective that does not change for gender here. It can be used with masculine or feminine nouns:

• documento fiscal
• nota fiscal

It does change for number, though:

• singular: fiscal
• plural: fiscais

In Brazilian Portuguese, nota fiscal eletrônica is a specific kind of official electronic tax invoice used in business and commerce. It is not just any casual note or receipt.

You will often see it abbreviated as NF-e.

So this phrase is very common in Brazilian administrative, financial, and business contexts.

Here pois means because, since, or as, introducing the reason for the first clause.

So the structure is:

• Arquivamos a nota fiscal eletrônica = main statement
• pois o documento é importante = reason

In this sentence, pois is functioning as an explanatory conjunction.

When pois introduces an explanatory clause after the main clause, Portuguese normally uses a comma:

..., pois ...

So Arquivamos a nota fiscal eletrônica, pois o documento é importante. is standard punctuation.

This comma helps show that the second part is explaining or justifying the first part.

Yes. You could say:

Arquivamos a nota fiscal eletrônica porque o documento é importante.

That is very natural too.

The difference is mostly one of style:

• porque is very common and neutral
• pois can sound a little more formal or more written

Both are correct here.

This avoids repeating the full expression.

After mentioning a nota fiscal eletrônica, the sentence refers back to it with the more general noun o documento. That is perfectly natural in Portuguese, just as English might say:

• We archived the electronic invoice because the document is important.

Also notice:

• nota is feminine → a nota
• documento is masculine → o documento

Even though the grammatical gender changes, both expressions refer to the same real-world item.

Portuguese uses ser for general, essential, or lasting characteristics, and estar for temporary states or conditions.

Here, the idea is that the document is important in a general sense, so é importante is the natural choice.

Using está importante would sound odd here, because it suggests a temporary condition rather than an inherent or general quality.

Many Portuguese adjectives ending in -e have the same form for masculine and feminine.

So:

• o documento é importante
• a nota é importante

Both are correct.

The adjective does change for number, though:

• singular: importante
• plural: importantes