Minha Carteira de Identidade Nacional está pronta.

Because carteira is a feminine singular noun.

In Portuguese, possessives agree with the thing possessed, not with the owner. So:

• minha carteira
• meu documento

Even if the speaker is male, they still say minha carteira, because carteira is feminine.

In Brazilian Portuguese, the definite article before a possessive is often optional.

So both of these are possible:

• Minha carteira de identidade nacional está pronta.
• A minha carteira de identidade nacional está pronta.

In Brazil, leaving out the article is very common, especially in neutral or formal statements like this one. Adding a can sound a little more emphatic, stylistic, or regional.

Because pronta describes a current state or condition: the ID is now ready.

Portuguese usually uses:

• ser for essential characteristics
• estar for temporary states, conditions, or situations

So:

• está pronta = it is ready
• é pronta would sound unnatural here

This is similar to the usual ser vs. estar distinction that learners often meet early on.

Because the adjective has to agree with carteira, which is feminine singular.

So:

• carteira ... pronta
• documento ... pronto
• carteiras ... prontas
• documentos ... prontos

The adjective matches the noun it describes.

In this context, pronta usually means something like:

• completed
• finished
• ready for pickup
• ready to be collected

So in a real-life administrative context, the sentence often means that the document has been processed and can now be received.

Here, de links nouns together.

The key part is:

• carteira de identidade

This is a very common Portuguese structure, where English might use a noun directly before another noun. English says identity card; Portuguese says literally something more like card of identity.

So de is just the normal way to connect those ideas.

Because in Portuguese, adjectives often come after the noun.

So:

• identidade nacional
• documento oficial
• carteira nova

That is the normal pattern. Sometimes adjectives can come before the noun, but that often changes the tone, style, or meaning. Here, nacional after the noun is the standard order.

Not always.

If you are treating Carteira de Identidade Nacional as the official name of the document, capitalization is common. That is especially true in formal notices, government contexts, or headings.

In ordinary running text, many people would write it in lowercase:

• Minha carteira de identidade nacional está pronta.

So the capitals are more about official-title style than basic grammar.

A rough pronunciation is MEEN-ya, but that is only approximate.

The important part is nh, which is a special Portuguese sound. It is similar to:

• the ñ in Spanish
• the ny sound in canyon

So minha is not pronounced like min-ha. The nh stays together as one sound.

Sometimes, especially in formal or official contexts, yes. But in everyday speech, people often shorten it.

Possible shorter versions include:

• Minha identidade está pronta.
• Seu documento está pronto.
• Seu RG está pronto.
• Sua CIN está pronta.

The exact wording depends on the situation, the region, and which document people are talking about. The full version sounds especially natural in official messages or announcements.