La declaración individual incluye la ganancia patrimonial.

In this context, declaración individual usually means an individual tax return or individual filing, not just a general statement.

In everyday Spanish, declaración can mean statement, declaration, or tax return, depending on context. In Spain, in financial or tax language, declaración very often refers to a tax declaration/return.

So here, declaración individual is most naturally understood as:

• an individual tax return
• as opposed to a joint one, for example declaración conjunta

Because both nouns are feminine singular:

• la declaración
• la ganancia

Spanish usually uses a definite article much more often than English does. So even if English might sometimes say something like Individual filing includes capital gain, Spanish normally keeps the articles:

• La declaración individual incluye la ganancia patrimonial.

This is completely natural Spanish.

Because the subject is singular:

• La declaración individual = singular subject
• therefore the verb is singular: incluye

The verb comes from incluir (to include).

A quick comparison:

• La declaración individual incluye... = The individual return includes...
• Las declaraciones individuales incluyen... = The individual returns include...

Incluye is:

• third person singular
• present tense
• from the verb incluir

So it can mean:

• he includes
• she includes
• it includes
• you include (formal usted)

In this sentence, it means it includes, because the subject is la declaración individual.

Because in Spanish, adjectives usually come after the noun.

So:

• ganancia = gain
• patrimonial = relating to assets/estate/property

That gives:

• ganancia patrimonial

This is the normal order in Spanish, especially in technical, legal, and financial language.

In Spain, ganancia patrimonial is a fairly technical term, especially in tax language. It usually refers to a capital gain or a gain arising from the sale or transfer of assets.

So although patrimonial might look like patrimonial in English, the phrase often corresponds more naturally to:

• capital gain

This is a good example of a phrase that should often be learned as a set expression, especially in legal or tax contexts.

Because individual and personal are not always interchangeable in Spanish.

• individual here means filed by one person alone
• personal would more often mean personal/private, and it would sound less natural in this tax context

In Spain, declaración individual contrasts naturally with:

• declaración conjunta = joint return

So individual is the correct word for this official meaning.

Not really. Patrimonial is more common in:

• legal language
• tax language
• administrative language
• formal writing

In everyday conversation, people may understand it, but it sounds formal and technical. A learner should recognize it, but you probably would not use it often in casual speech.

Usually, no—not in this sentence.

Incluir normally takes a direct object, and here the object is presented as a specific category/item:

• incluye la ganancia patrimonial

Leaving out la would sound incomplete or unnatural in standard Spanish in this context.

Because patrimonial is an adjective, not a noun.

So:

• ganancia patrimonial = noun + adjective

If Spanish used a noun instead, then a structure with de might appear. But here patrimonial directly describes ganancia, so no preposition is needed.

Yes, very likely.

Several clues point to that:

• declaración often means tax return in administrative contexts
• individual suggests a type of filing
• ganancia patrimonial is a technical tax/legal term in Spain

So a learner should probably read this as formal administrative Spanish rather than everyday conversation.

The plural would be:

• Las declaraciones individuales incluyen las ganancias patrimoniales.

Changes:

• La → Las
• declaración → declaraciones
• individual → individuales
• incluye → incluyen
• la ganancia → las ganancias

This is a useful way to see agreement clearly.

Declaración is pronounced roughly like:

• deh-klah-rah-THYON in most of Spain
• deh-klah-rah-SYON in Latin American varieties and some parts of Spain

The written accent in -ción shows where the stress falls:

• declaraCIÓN

Without the accent mark, the stress rules would suggest a different pronunciation, so the accent is necessary.