Si cambias el encabezado o el índice, habrá que revisar también el resto del apartado.

Because Spanish normally uses this pattern for a real, possible condition:

• si + present indicative
• then a main clause in the present, future, imperative, etc.

So:

• Si cambias... = If you change...
• ..., habrá que revisar... = ..., it will be necessary to review...

In standard Spanish, you do not normally use the future after si in this kind of sentence, so si cambiarás would be wrong here.

And si cambies is also wrong because si does not usually trigger the subjunctive in ordinary if clauses about real possibilities.

This is the impersonal structure haber que + infinitive, which means it is necessary to... or one has to...

Here:

• habrá que = it will be necessary to
• revisar = review / check

So habrá que revisar literally means something like there will be a need to review.

It is impersonal, so it does not say exactly who has to do it. That makes it sound less direct than:

• tendrás que revisar = you will have to review

In a document, instruction, or workplace context, habrá que often sounds natural because it focuses on the task, not on the person.

Cambias is the tú form of cambiar in the present indicative, so the sentence is addressing one person informally.

• si cambias = if you change (informal singular)

Other possibilities would be:

• si cambia = if you change (formal usted) / if he/she changes
• si cambiáis = if you all change (vosotros, common in Spain)
• si cambian = if you all change (ustedes) / if they change

So this sentence is written to one person in an informal way.

Encabezado usually means heading or header.

In this kind of context, it probably refers to a document element such as:

• the heading of a section
• a title line
• a header in a form, file, or page layout

So it is not necessarily a full title of the whole document; it is more likely a heading attached to this particular part.

Índice can mean different things depending on context, including:

• index
• table of contents
• sometimes a numbered outline or listing

In document-related Spanish, especially in Spain, índice very often means table of contents.

So in this sentence, it most likely refers to some structural element of the document that affects the rest of the section if changed.

It means the rest of the section.

Breakdown:

• el resto = the rest
• del = de + el = of the
• apartado = section, part, entry, or item, depending on context

In Spanish from Spain, apartado is very commonly used for a section of a document, form, set of instructions, or text.

So el resto del apartado means the remaining content in that section.

Because the sentence begins with a conditional clause:

• Si cambias el encabezado o el índice, ...

When this kind of si clause comes first, Spanish normally separates it from the main clause with a comma.

So this is standard punctuation:

• Si cambias..., habrá que...

If the order were reversed, the comma would usually disappear:

• Habrá que revisar también el resto del apartado si cambias el encabezado o el índice.

También means also or too.

In this sentence, it shows that the rest of the section will also need checking, not just the heading or the index.

So:

• habrá que revisar también el resto del apartado

means roughly:

• the rest of the section will also have to be reviewed

Its position is flexible in Spanish, but different placements can shift the emphasis slightly. For example:

• También habrá que revisar el resto del apartado = emphasis a bit more on also
• Habrá que revisar también el resto del apartado = very natural here; emphasis on the rest of the section too

Because the conjunction o only changes to u before words that begin with an o sound, such as:

• siete u ocho
• uno u otro

It does not change before an i sound.

A common confusion is with y, which can change to e before an i sound:

• padre e hijo

But here the word is índice, so the correct form is:

• el encabezado o el índice

Because the sentence refers to specific, known parts of a document.

• el encabezado = the heading
• el índice = the index / table of contents
• el resto = the rest
• del apartado = of the section

Spanish often uses definite articles where English might sometimes be a bit looser, especially when talking about parts of a known object, text, or document.

Also, del is just the contraction of:

• de + el → del

So del apartado literally means of the section.

No. They are different.

• apartado = section / subsection / item
• párrafo = paragraph

So el resto del apartado means the rest of the section, not just the rest of the paragraph.

This matters because apartado usually refers to a larger structural unit in a document than párrafo does.

Yes, in natural English it often could.

Even though habrá que revisar is literally impersonal, in context it may function like:

• you’ll have to review the rest of the section too

That said, the Spanish is slightly less direct because it avoids naming the person responsible.

So the difference is:

• habrá que revisar = more impersonal, more neutral
• tendrás que revisar = directly telling you what you must do

Spanish often prefers the impersonal version in instructions, editing comments, and professional communication.