A informação é verdadeira.

Because a is the feminine singular definite article, meaning the.

• a informação = the information
• o livro = the book (masculine)
• a casa = the house (feminine)

In Portuguese, the definite article is used more often than in English. So where English might sometimes just say information, Portuguese often says a informação when referring to specific information.

Because Portuguese usually uses ser for something seen as an inherent quality, fact, or identification.

Here, verdadeira means true, so A informação é verdadeira means the information is true in itself.

• é = from ser
• está = from estar

With verdadeiro/verdadeira, ser is the normal choice:

• A história é verdadeira. = The story is true.
• Isso é verdade. = That is true.

Using estar here would sound unnatural in standard usage.

Because adjectives in Portuguese usually agree with the noun in gender and number.

informação is a feminine singular noun, so the adjective must also be feminine singular:

• informação verdadeira
• not informação verdadeiro

Compare:

• o facto verdadeiro = the true fact
• a informação verdadeira = the true information

So verdadeira matches informação.

You can tell from the article: a informação.

In Portuguese, the article usually shows the noun’s gender:

• o = masculine singular
• a = feminine singular

So even if the word ending is not obviously feminine, the article tells you.

Also, many nouns ending in -ção are feminine:

• a informação
• a situação
• a tradução
• a nação

This is a very useful pattern to remember.

A helpful learner-friendly approximation is:

a in-for-ma-SÃO é ver-da-DEI-ra

A few important points for European Portuguese:

• informação is stressed on the last syllable: -ção
• verdadeira is stressed on -dei-
• é sounds like the e in bed
• ão is nasal, which is one of the harder sounds for English speakers

Also, in European Portuguese, unstressed vowels are often reduced, so the sentence may sound more compressed than you expect from the spelling.

They do different jobs.

é

• The accent shows this is the verb is
• It also shows the vowel is stressed and open
• It helps distinguish it from e, which means and

So:

• é = is
• e = and

informação

• The ã shows a nasal vowel
• The ending -ão is pronounced nasally, not like plain ao

So the marks are important both for meaning and pronunciation.

Yes, it is singular here.

Like English information, Portuguese informação can be used as a general or mass noun. But Portuguese also uses the plural informações quite naturally when talking about separate pieces of information, details, or information sources.

Examples:

• A informação é verdadeira. = The information is true.
• As informações são verdadeiras. = The pieces of information / the details are true.

So both singular and plural exist, depending on context.

Yes, absolutely.

• A informação é verdadeira. = The information is true.
• Esta informação é verdadeira. = This information is true.

Esta makes it more specific and immediate, as if you are pointing to a particular piece of information.

In many real-life situations, esta informação may sound more natural if you are referring to something just mentioned or shown.

Not exactly, though they can overlap.

• verdadeira = true, not false
• correta = correct, accurate

Sometimes both work:

• A informação é verdadeira.
• A informação está correta.

But the nuance is slightly different:

• verdadeira focuses on truth
• correta focuses on correctness or accuracy

So if you want to stay very close to true, verdadeira is the better choice.

Yes, but it changes the structure and slightly changes the emphasis.

Your sentence is:

• A informação é verdadeira.
  = The information is true.

If you move the adjective before the noun, you get something like:

• A verdadeira informação...

That no longer means exactly the same thing. It sounds more like:

• the true/real information

So:

• A informação é verdadeira = statement about the information
• A verdadeira informação = noun phrase describing a kind of information

For the meaning in your sentence, the original version is the natural one.

Yes, it is grammatical and natural.

It sounds like something you might say when confirming whether some information is true or false.

Depending on context, native speakers might also say:

• Essa informação é verdadeira.
• Esta informação é verdadeira.
• A informação está correta.

But A informação é verdadeira is perfectly good Portuguese.