Aquest arxiu és important perquè el document de la reunió és a la carpeta.

Because arxiu is a masculine singular noun, so the demonstrative has to match it.

• aquest = this, masculine singular
• aquesta = this, feminine singular

So:

• aquest arxiu = this file
• aquesta carpeta = this folder

Catalan demonstratives agree in gender and number with the noun.

Arxiu can mean file or archive, depending on context.

In this sentence, it most naturally means file, especially because the sentence also mentions a document and a folder. That makes it sound like either:

• a computer file in a folder, or
• a paper file/archive item in a physical folder

So the exact interpretation depends on context, but file is the most likely meaning here.

Because both parts of the sentence need a verb, and in both places the verb is ser in the third person singular:

• Aquest arxiu és important
• el document de la reunió és a la carpeta

Here és means is.

In the first part, it links the subject to an adjective:

• arxiu
  • és
    • important

In the second part, it gives the location of the document:

• document
  • és
    • a la carpeta

So the repeated és is completely normal.

This is something that often surprises English speakers, especially if they also know Spanish.

In standard Catalan, ser is often used to express the location of things:

• El llibre és a la taula = The book is on the table
• El document és a la carpeta = The document is in the folder

So és a la carpeta is normal Catalan.

In some varieties, you may also hear estar in location expressions, but for a simple statement of where something is, ser is very common and standard.

Because perquè as one word means because.

So in this sentence:

• perquè = because

Compare:

• perquè = because
• per què = why / for what reason

Examples:

• Ho faig perquè és necessari. = I do it because it is necessary.
• Per què ho fas? = Why are you doing it?

So here perquè introduces the reason.

It means of the meeting or from the meeting, and it tells you which document we are talking about.

• el document = the document
• de la reunió = of the meeting

Together:

• el document de la reunió = the meeting document / the document from the meeting

This is a very common Catalan structure:

• el llibre del professor = the teacher’s book
• la porta de la casa = the door of the house
• el resum de la reunió = the summary of the meeting

So de often does the job that English sometimes expresses with ’s or with a noun used as an adjective.

In standard Catalan, a is very commonly used for location:

• és a casa = is at home
• és a l’oficina = is at the office
• és a la carpeta = is in the folder

In some contexts and varieties, en can also appear, especially before certain kinds of place expressions, but a la carpeta is perfectly normal and standard.

Also note that:

• a + la does not contract
• so it stays a la

But with masculine singular articles, you do get contraction:

• a + el = al

For example:

• és al despatx = is in/at the office

Because Catalan often uses the definite article where English also uses the.

• la reunió = the meeting
• la carpeta = the folder

In el document de la reunió, the article shows that it is a specific meeting, not just any meeting.

And in a la carpeta, it refers to a specific folder already known from the context.

Catalan uses articles very regularly, so learners should get used to seeing them often.

Because important is an adjective that has the same form for masculine and feminine singular.

So you get:

• un arxiu important
• una carpeta important

But the plural changes:

• arxius importants
• carpetes importants

Many Catalan adjectives work like this: same singular form for both genders, then -s in the plural.

Reunió is pronounced roughly like ray-oo-NYO or reh-oo-nee-O, depending on accent and how closely you want to approximate Catalan sounds.

The written accent in reunió shows that the stress falls on the last syllable:

• re-u-ni-ó

That accent is important, because without it, the stress pattern would be interpreted differently.

So the accent is not optional: it tells you how the word should be stressed.

The sentence has two clauses joined by perquè:

1. Aquest arxiu és important
2. perquè el document de la reunió és a la carpeta

So the pattern is:

• [statement] + perquè + [reason]

That is a very common and useful structure in Catalan.

You can build many similar sentences with it:

• Aquest correu és útil perquè té la informació correcta.
• Aquesta carpeta és important perquè hi ha els contractes.

So this sentence is a good model for expressing reason.

Yes. Catalan allows some flexibility, although the original version is the most neutral.

For example, you could also say:

• Aquest arxiu és important perquè a la carpeta hi ha el document de la reunió.

That version places more focus on the folder as the location.

But the original sentence is simpler and very natural:

• Aquest arxiu és important perquè el document de la reunió és a la carpeta.

For learners, the original order is a very good standard pattern to remember.