A guia de pagamento está no aplicativo.

In Brazilian Portuguese, guia de pagamento usually refers to a payment slip, payment form, or payment document—something you use to make a payment.

The exact English translation depends on context. For example, it could be:

• a payment slip
• a billing form
• a payment document

So guia here does not mean a tour guide or a guidebook. It means a document related to payment.

Because guia can be either feminine or masculine depending on the meaning.

• a guia = a guide/document/form, or sometimes a guidebook
• o guia = a male guide, such as a tour guide

In this sentence, guia is a document, so Portuguese uses the feminine article a.

De pagamento means of payment or more naturally in English, for payment / related to payment.

It tells you what kind of guia it is:

• guia = guide/form/document
• guia de pagamento = payment form/document

This de + noun structure is extremely common in Portuguese:

• cartão de crédito = credit card
• conta de luz = electricity bill
• comprovante de pagamento = proof of payment

Because está is used for location here.

In Portuguese, estar is normally used to say where something is:

• O livro está na mesa. = The book is on the table.
• A guia de pagamento está no aplicativo. = The payment slip is in the app.

Using é here would sound wrong, because ser is generally not used for physical or virtual location in this kind of sentence.

No aplicativo means in the app.

It is a contraction:

• em = in
• o = the
• em + o = no

So:

• no aplicativo = in the app

Other common contractions:

• na = em + a
• nos = em + os
• nas = em + as

Examples:

• na escola = in the school
• no celular = on the phone / in the phone
• nos arquivos = in the files

Portuguese uses definite articles much more often than English.

So no aplicativo literally means in the app, referring to a specific app that both speakers understand from context.

Saying em aplicativo would usually sound incomplete or unnatural here. You would normally expect:

• no aplicativo = in the app
• em um aplicativo = in an app

Yes. In Brazilian Portuguese, aplicativo is the standard word for app.

For example:

• Baixe o aplicativo. = Download the app.
• O aplicativo do banco = the bank app

In casual speech, some people may also say app, but aplicativo is the full and very common Portuguese word.

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

• A guia de pagamento está no aplicativo.

This structure is very common:

• subject + verb + location

You could change the order in some contexts, such as:

• No aplicativo está a guia de pagamento.

But that sounds more marked or formal, and it is not the usual everyday phrasing. For a learner, the original sentence is the best pattern to follow.

Portuguese often uses articles where English may or may not use them.

In A guia de pagamento está no aplicativo, both nouns have articles:

• a guia
• o aplicativo → contracted in no aplicativo

This is very normal in Portuguese. It often sounds more natural to specify the noun with an article, especially when the speaker is referring to something already known in the situation.

The plural would be:

• As guias de pagamento estão no aplicativo.

Changes:

• a → as
• guia → guias
• está → estão

Notice that de pagamento stays the same here.

Guia is pronounced roughly like GHEE-ah, with two syllables:

• gui-a

A few pronunciation notes:

• The g in gui sounds like the g in give, not like the g in giant
• The u is not strongly pronounced on its own; it helps form the gi sound
• The stress is usually on the first syllable: GUI-a

Yes, in natural English, in the app and on the app can both work depending on context.

Portuguese uses em here, which is very broad and often translates as:

• in
• on
• at

So no aplicativo literally comes from em + o aplicativo, and English chooses the most natural option. In many cases, in the app is the best translation, but on the app may also sound natural in English conversation.

It is neutral and completely natural in everyday Brazilian Portuguese.

It would work well in many contexts:

• customer service
• banking
• tax or billing systems
• workplace communication
• everyday conversation about an app

It is neither especially formal nor especially casual.