El oficial revisa el documento.

Oficial can refer to a man or a woman, but the article shows the gender:

• el oficial = a male official/officer
• la oficial = a female official/officer

So in this sentence, el tells you the person is masculine.

Here, oficial is a noun because it is the person doing the action.

You can tell because it comes after the article el and acts as the subject of the sentence.

As an adjective, oficial would describe another noun, for example:

• un documento oficial = an official document

So in El oficial revisa el documento, oficial is not describing documento. It is the person.

Revisar is the infinitive, the basic dictionary form meaning to check / to review / to inspect.

In a normal sentence, Spanish usually needs a conjugated verb.
Revisa is the third-person singular present form of revisar.

So:

• revisar = to check
• revisa = he checks / she checks / it checks

Because the subject is el oficial, the verb has to match it, so revisa is the correct form.

Spanish often does not use subject pronouns when they are not needed.

The verb ending already shows the person and number, and here the subject is also clearly stated as el oficial, so adding él would be unnecessary in most contexts.

• El oficial revisa el documento = normal, natural
• Él revisa el documento = possible, but only if the subject is already known
• Él, el oficial, revisa el documento = more emphatic than usual

Spanish uses pronouns like él or ella mainly for emphasis, contrast, or clarity.

In this kind of sentence, revisar usually means something like:

• to check
• to inspect
• to examine
• to look over
• sometimes to review

The best choice depends on context. If an official is looking at paperwork, ID, or forms, check or inspect is often the most natural idea.

So revisar is broader than just one English verb.

El documento refers to a specific document, one that is identifiable in the situation.

Spanish uses the definite article very often when the speaker and listener are expected to know which thing is meant.

Compare:

• el documento = the document, a specific one
• un documento = a document, any one document / one not yet identified

So this sentence suggests there is a particular document being checked.

It can mean either one, depending on context.

The Spanish simple present often covers both:

• a general or habitual action: The official checks the document
• an action happening now: The official is checking the document

If Spanish wants to make the ongoing action especially clear, it can use:

• El oficial está revisando el documento

But the simple present revisa is still very common and natural.

This is the normal, neutral word order: subject + verb + object.

Spanish can change word order for emphasis, style, or contrast, but the basic version is the best one for learners.

For example, you might see something like:

• El documento lo revisa el oficial

That gives special emphasis to the document or to who is checking it.
But in ordinary, straightforward speech, El oficial revisa el documento is the safest pattern.

In most of Spain, oficial is pronounced approximately o-fi-THYAL.

A few useful pronunciation points:

• The stress is on the last syllable: ofiCIAL
• The ci in much of Spain sounds like the th in think
• So oficial sounds different from many Latin American pronunciations, where it is more like o-fi-SYAL

The other words are approximately:

• revisa = reh-BEE-sa or reh-VEE-sa to English ears, though the Spanish v is not a strong English v
• documento = do-koo-MEN-to

They use el for different reasons:

• el oficial: masculine because the person is male
• el documento: masculine because documento is a masculine noun

In Spanish, each noun has grammatical gender, and the article must agree with it.

So if you changed the first noun to a female official, you would get:

• La oficial revisa el documento

But documento would still stay masculine:

• el documento