Recebi a informação ontem.

Recebi is the 1st person singular form of receber (to receive) in the pretérito perfeito of the indicative, which is the normal simple past for a completed action.

So:

• receber = to receive
• recebi = I received

In this sentence, it tells you that the action happened and was completed in the past.

Portuguese often drops subject pronouns when the verb form already makes the subject clear.

So:

• Recebi a informação ontem.
• Eu recebi a informação ontem.

Both mean the same thing: I received the information yesterday.

The version without eu sounds very natural in Brazilian Portuguese. You might add eu for emphasis, contrast, or clarity.

Example:

• Eu recebi a informação, mas ele não.
  I received the information, but he didn’t.

The a here is the definite article, meaning the.

So:

• a informação = the information
• uma informação = a piece of information / some information

Portuguese uses articles more often than English does, so seeing a here is very normal.

The difference is mainly definiteness:

• a informação = the information
  This usually refers to specific information already known in the context.
• uma informação = a piece of information / some information
  This introduces something less specific or new.

Compare:

• Recebi a informação ontem. = I received the information yesterday.
• Recebi uma informação ontem. = I received some / a piece of information yesterday.

Informação works a lot like information in English: it is often used as a mass noun or uncountable idea.

So a informação can mean:

• the information
• the relevant information
• the piece of information, depending on context

Portuguese can also use the plural:

• as informações = the pieces of information / the information (plural)

But in many cases, singular informação is perfectly natural.

Putting ontem at the end is a very natural word order in Portuguese.

• Recebi a informação ontem.

But Portuguese is flexible, and you can also say:

• Ontem, recebi a informação.

This version puts more emphasis on yesterday.

So both are correct:

• Recebi a informação ontem.
• Ontem, recebi a informação.

The difference is mostly one of emphasis and style, not basic meaning.

Because the sentence describes a completed event that happened yesterday.

• recebi = I received / I did receive
  completed action
• recebia = I was receiving / I used to receive
  ongoing, repeated, habitual, or background action in the past

So:

• Recebi a informação ontem.
  I received the information yesterday.
  One completed event.

If you said:

• Recebia a informação...
  it would sound incomplete or would suggest a different kind of past meaning.

In Brazilian Portuguese, informação is approximately pronounced like:

een-for-ma-SOWN

A few important points:

• the final -ção is very common in Portuguese
• it sounds roughly like sown, but with a nasal ending
• the ã sound is nasal, not a plain a
• the stress is on the last syllable: ção

A more detailed approximation is:

• in-for-ma-SÃW

Not exact English, but close enough to help.

The accent in informação helps show stress and pronunciation.

In informação:

• the written accent is on ã
• it indicates a nasal sound
• the stressed part is the ending -ção

So the word is stressed near the end, not like:

• inforMAcao
• INformacao

but rather:

• informaÇÃO

Accent marks in Portuguese are important because they often tell you how to pronounce the word correctly.

Yes, absolutely.

• Recebi a informação ontem.
• Eu recebi a informação ontem.

Both are correct.

The version without eu is usually more neutral and natural in everyday Portuguese. The version with eu may sound more emphatic, especially if you are contrasting speakers or clarifying who did the action.

Yes, it is natural.

Receber a informação means something like:

• to receive the information
• to be informed
• to get the information

Depending on context, Brazilians might also say things like:

• Recebi a notícia ontem. = I received the news yesterday.
• Fui informado ontem. = I was informed yesterday.
• Soube disso ontem. = I found out about that yesterday.

But Recebi a informação ontem is grammatically correct and perfectly understandable.

Yes. Ontem is fairly mobile in the sentence.

Possible versions:

• Recebi a informação ontem.
• Ontem, recebi a informação.
• Recebi ontem a informação.

The first two are the most common and natural.
The third is possible, but it can sound more formal, literary, or marked depending on context.

The structure is:

[verb] + [object] + [time expression]

Breaking it down:

• Recebi = verb
• a informação = direct object
• ontem = time expression

If you include the subject pronoun, it becomes:

[subject] + [verb] + [object] + [time expression]

• Eu recebi a informação ontem.

This is a very common pattern in Portuguese.