A certidão de nascimento está na pasta azul.

A is the feminine singular definite article, meaning the.

It appears here because certidão is a feminine singular noun: a certidão = the certificate.

In Portuguese, definite articles are used more often than in English, especially with specific objects that both speaker and listener can identify.

Word by word:

• certidão = certificate / official document
• de = of
• nascimento = birth

So literally, certidão de nascimento is certificate of birth.
In natural English, that is birth certificate.

Portuguese often connects nouns with de where English prefers a noun used like an adjective.

So:

• certidão de nascimento = birth certificate
• literally: certificate of birth

This noun + de + noun pattern is very common in Portuguese.

It uses está because the sentence is talking about location: where the birth certificate is.

In Portuguese, estar is normally used for location:

• A certidão está na pasta azul. = The birth certificate is in the blue folder.

If you used é, it would sound wrong here, because ser is not normally used to say where an object is located.

Na is a contraction of:

• em = in / on / at
• a = the

So:

• em + a = na

Because pasta is feminine singular, you get:

• na pasta = in the folder

This kind of contraction is very common in Portuguese.

Here, pasta means folder or file folder, not food.

This is a classic false friend for English speakers.

Depending on context, pasta in Portuguese can mean things like:

• folder
• briefcase/file holder
• paste/spread

But in this sentence, pasta azul clearly means blue folder.

In Portuguese, adjectives usually come after the noun.

So:

• pasta azul = blue folder
• literally: folder blue

That is the normal, neutral order.
English usually puts adjectives before the noun, but Portuguese often puts them after.

Not all Portuguese adjectives change for gender.

Azul stays the same in the singular for both masculine and feminine nouns:

• o carro azul = the blue car
• a pasta azul = the blue folder

But in the plural, it does change:

• os carros azuis
• as pastas azuis

So azul has:

• singular: azul
• plural: azuis

You know they are feminine because they take the article a:

• a certidão
• a pasta

Also, na in na pasta confirms that pasta is feminine, because na = em + a.

While noun endings can give clues, the safest way is to learn the noun together with its article:

• a certidão
• a pasta

In normal Portuguese, that would sound unnatural.

The natural sentence is:

• A certidão de nascimento está na pasta azul.

Portuguese usually prefers the article with a specific noun like this.
Leaving it out might only happen in very special styles, like notes, labels, or headlines.

Here it means in the blue folder.

The preposition em can correspond to English in, on, or at, depending on context. In this sentence, the natural meaning is that the document is inside the folder.

So:

• na pasta azul = in the blue folder

A simple pronunciation guide is:

ah sehr-chee-DAWNG jee nah-see-MEN-too es-TAH nah PAHS-tah ah-ZOOL

A few important points for English speakers:

• certidão has a nasal ending -ão
• de often sounds like jee in Brazilian Portuguese before certain sounds
• nascimento has sc pronounced like s
• está is stressed on the last syllable: es-TA
• azul is stressed on the last syllable: a-ZUL

If you want to sound more natural, the nasal sounds in certidão are especially important.

Yes, but the original order is the most neutral and natural:

• A certidão de nascimento está na pasta azul.

Portuguese can change word order for emphasis, but that is less basic and less common for learners. For example, moving parts around might sound more dramatic, literary, or context-dependent.

So as a beginner, the best pattern to remember is:

subject + estar + location