La cuenta justificativa incluye los justificantes de gasto.

In Spanish, it is very common to use the definite article with nouns when talking about a specific document, concept, or item already known from the context. Here, la cuenta justificativa means the supporting account/report or the statement of justification.

You could sometimes omit the article in headings or labels, but in a normal sentence, la sounds natural and standard.

Justificativa is an adjective meaning supporting, justifying, or used to justify something.

It agrees with cuenta, which is feminine singular:

• cuenta → feminine singular
• justificativa → feminine singular

So cuenta justificativa is literally something like justifying/supporting account/report.

Because the subject is singular: la cuenta justificativa.

The verb incluir must match the subject:

• la cuenta justificativa incluye = the supporting report includes
• las cuentas justificativas incluyen = the supporting reports include

So incluye is the third-person singular form.

Yes, they are related. Both come from the idea of justifying or providing proof.

But they have different grammatical roles here:

• justificativa = adjective describing cuenta
• justificantes = plural noun meaning supporting documents, receipts, or proofs

So:

• cuenta justificativa = the report/account that serves to justify expenses
• justificantes de gasto = the documents that prove the expenses

It usually refers to documents proving an expense, such as:

• receipts
• invoices
• tickets
• proof of payment

Literally:

• justificantes = supporting documents / proofs
• de gasto = of expense / for expenditure

In administrative or legal Spanish, this phrase is very common.

Here, de gasto is being used in a general, category-like sense: expense-related or for expenditure.

Spanish often uses de + singular noun to classify something:

• centro de salud = health centre
• tarjeta de crédito = credit card
• justificantes de gasto = expense receipts/supporting expense documents

If you said del gasto, it would usually refer to one specific expense already known.
If you said de los gastos, it would mean of the expenses, referring to specific expenses in context.

Yes, cuenta literally often means account, but in administrative Spanish it can have broader meanings depending on context.

In this phrase, it refers to a formal statement, report, or accounting record that explains and supports how money was spent.

So although account is the literal word, the best English translation often depends on the context:

• supporting report
• statement of expenditure
• justification report
• supporting account

Because the sentence is talking about:

• one report: la cuenta justificativa
• several supporting documents: los justificantes de gasto

So the structure is:

• singular subject
  • singular verb
    • plural object

That is perfectly normal:

• La carpeta contiene los documentos.
• El informe incluye los anexos.

Same pattern here:

• La cuenta justificativa incluye los justificantes de gasto.

Sometimes yes, but not always.

Recibos usually means receipts, but justificantes is broader and more formal. It can include:

• receipts
• invoices
• payment confirmations
• other proof documents

So in official or administrative Spanish, justificantes is often better because it covers more than just simple receipts.

In Spain Spanish, it is pronounced approximately like:

hoos-tee-fee-KAN-tes

A few useful pronunciation points:

• j sounds like a strong English h, but rougher: ju
• ci sounds like thi in most of Spain, so justificantes has a th sound there
• the stress falls on kan: jus-ti-fi-CAN-tes

In many Latin American accents, ci would sound like si instead.

Yes, it is quite formal and administrative. You are likely to see this kind of sentence in:

• official forms
• grant documentation
• accounting paperwork
• public administration texts

In everyday conversation, people might say something simpler depending on the situation, but this sentence sounds perfectly natural in official Spanish from Spain.