Formalizo o negócio, me cadastro e declaro o faturamento.

Because the sentence is in the first person singular of the present tense: I formalize / I register / I declare.

• formalizar → formalizo
• cadastrar(-se) → (me) cadastro
• declarar → declaro

In Brazilian Portuguese, the eu pronoun (I) is often omitted because the verb ending already shows who the subject is. So:

• Formalizo o negócio = I formalize the business
• Me cadastro = I register myself / I sign up
• Declaro o faturamento = I declare the revenue

If you wanted to include the subject for emphasis, you could say:

• Eu formalizo o negócio, me cadastro e declaro o faturamento.

Portuguese often drops subject pronouns when the verb form makes the subject clear. This is called a null-subject or pro-drop language feature.

Here, the endings -o in formalizo, cadastro, and declaro clearly indicate eu (I), so saying eu is optional.

• Formalizo o negócio sounds natural.
• Eu formalizo o negócio is also correct, but slightly more explicit or emphatic.

English usually requires the subject pronoun, but Portuguese often does not.

Formalizar o negócio means to make the business official/legal/formal.

Depending on context, it can mean things like:

• legally establishing the business
• regularizing the business
• turning an informal business into a registered one

So formalizo o negócio is not just I make the deal formal here. In Brazilian Portuguese, negócio can mean business in the sense of a commercial activity or enterprise.

Portuguese uses definite articles much more often than English.

So o negócio literally means the business, but in English we might simply say the business or sometimes just my business, depending on context.

Using the article here is completely normal in Portuguese. In many cases where English would omit an article, Portuguese keeps it.

Because cadastrar-se is often used as a pronominal/reflexive-style verb in Portuguese when the subject is registering themselves.

• cadastrar = to register something / to enter something into a system
• cadastrar-se = to register oneself / to sign up

So:

• Cadastro a empresa no sistema = I register the company in the system
• Me cadastro no sistema = I register myself in the system / I sign up in the system

In your sentence, me cadastro means the speaker is the person being registered.

In practice, it is usually closer to I sign up / I register myself, not strongly reflexive in the literal English sense.

Portuguese often uses clitic pronouns like me, se, nos with verbs that are not always translated with myself/yourself in English.

So although me cadastro literally looks like I register myself, the most natural English translation is often simply:

• I sign up
• I register

This is very common with pronominal verbs in Portuguese.

That is called proclisis: the object/reflexive pronoun appears before the verb.

In everyday Brazilian Portuguese, me cadastro is the most natural order.

You may also see forms like:

• cadastro-me

But that sounds more formal, literary, or European Portuguese-like. In normal spoken Brazilian Portuguese, me cadastro is much more common.

Yes, grammatically it can be, but in Brazilian Portuguese it sounds quite formal or unnatural in ordinary speech.

Compare:

• Me cadastro → normal, natural in Brazil
• Cadastro-me → grammatically possible, but formal/literary/stiff

For a learner of Brazilian Portuguese, me cadastro is the form you should expect and usually use.

Faturamento usually means revenue, gross sales, or turnover, depending on context.

It is related to the money the business bills or brings in, not necessarily its profit.

So:

• faturamento ≠ profit
• it is usually closer to gross income/revenue

That matters because in business contexts, declaro o faturamento means reporting how much money came in, not how much was earned after expenses.

Portuguese often leaves out possessives when ownership is obvious from context.

Since the speaker is talking about their own business process, o faturamento naturally means the revenue of that business, so meu is not necessary.

Both are possible:

• declaro o faturamento = natural
• declaro meu faturamento = also possible, but more explicit

Portuguese often prefers the simpler version when the meaning is already clear.

The sentence lists a sequence of actions:

1. Formalizo o negócio
2. me cadastro
3. e declaro o faturamento

This is a normal way to present steps in Portuguese. The commas separate the actions, and e (and) links the final one.

It has a procedural feel, like someone describing a process:

• I formalize the business, register myself, and declare the revenue.

The present tense here can have a few possible interpretations depending on context:

• right now / currently: I am doing this
• habitual: I do this
• procedural/instructional: I do this, then this, then this

In a sentence like this, it often sounds like a process description or a step-by-step explanation, especially if it appears in business or administrative language.

So it may be less about what is happening at this exact moment and more about the actions taken in the process.

Sometimes, yes, depending on context.

Portuguese simple present can correspond to different English forms:

• I formalize
• I’m formalizing
• I do formalize

But without more context, the safest interpretation is usually the plain present or a process-style present:

• I formalize the business, register myself, and declare the revenue.

If the context clearly shows the speaker is in the middle of the process right now, English might prefer:

• I’m formalizing the business, registering myself, and declaring the revenue.

No, negócio is a very flexible word in Portuguese. It can mean:

• business
• deal
• thing/stuff in informal speech

Examples:

• abrir um negócio = to start a business
• fechar um negócio = to close a deal
• me passa aquele negócio ali = pass me that thing there

In your sentence, because of formalizo and faturamento, negócio clearly means business.

Possibly, but it changes the wording and may sound less natural depending on context.

• formalizo o negócio emphasizes making the business legally/formally established
• registro o negócio emphasizes registering the business
• me cadastro is commonly used for signing oneself up / registering oneself in a system

Also, me registro exists, but me cadastro is often more common when dealing with forms, systems, platforms, or administrative enrollment.

So your original sentence has a specific bureaucratic/business flavor that is quite natural.

The base verb is usually given as cadastrar or cadastrar-se.

Both are useful to know:

• cadastrar = to register, to enter into a register/system
• cadastrar-se = to register oneself, to sign up

In dictionary form, you may see either one depending on how the verb is being presented.

For your sentence, the full idea is best understood through cadastrar-se.

It sounds neutral to somewhat formal, especially because of the business/bureaucratic vocabulary:

• formalizo
• cadastro
• declaro
• faturamento

These are not slangy or casual words. The sentence feels like something you might see in:

• an explanation of official procedures
• a government/business webpage
• a summary of administrative steps

At the same time, the pronoun placement me cadastro is very natural in everyday Brazilian Portuguese, so it does not sound overly stiff.