La destinataria firmó el aviso y el remitente guardó una copia en la carpeta.

Because the two nouns behave differently in terms of grammatical gender:

• la destinataria is the feminine form of destinatario / destinataria (“recipient” or “addressee”).
• el remitente is a noun ending in -ente, which often has the same form for both male and female people. The article changes instead:
  • el remitente = the male sender
  • la remitente = the female sender

So here, the sentence specifically refers to:

• a female recipient
• a male sender

Destinataria means recipient, addressee, or the person something is intended for.

In this kind of context, it often refers to:

• the person receiving a letter or package
• the person named as the destination of a document or delivery

It is the feminine form of destinatario.

Aviso is a flexible word in Spanish. It can mean:

• notice
• notification
• slip
• message
• advice/warning in some contexts

In this sentence, because someone signed it, aviso likely means some kind of notice slip, delivery notice, or receipt notice.

So it is probably not a general “warning,” but a document or paper that can be signed.

Both firmó and guardó are in the preterite tense, which is used for completed actions in the past.

• firmó = he/she signed
• guardó = he/she kept / put away / stored

These forms come from:

• firmar → firmó
• guardar → guardó

The preterite is used here because the sentence describes two finished actions:

1. the recipient signed the notice
2. the sender kept a copy in the folder

The accent marks show the correct stress and also help distinguish these forms.

• firmó = he/she signed
• guardó = he/she kept

Without the accent:

• firmo = I sign / I do sign
• guardo = I keep / I do keep

So the accent is important because it changes the meaning from first person singular present to third person singular preterite.

Spanish often omits subject pronouns when the verb ending already makes the subject clear enough.

So instead of saying:

• La destinataria firmó
  Spanish does not need to add ella.

And instead of:

• el remitente guardó
  it does not need él.

The nouns themselves already identify who did the action, so extra pronouns would usually be unnecessary.

Una copia means a copy, so it introduces the copy as non-specific or new information.

If it said la copia, it would sound like:

• the copy
• a copy already known or previously mentioned

In this sentence, una copia simply means the sender kept a copy in the folder.

Guardar can mean several related things, including:

• to keep
• to store
• to put away
• to save

In this sentence, guardó una copia en la carpeta suggests:

• he kept a copy
• he filed a copy
• he put away a copy in the folder

So kept is a good translation, but the Spanish verb also carries the idea of placing/storing something somewhere.

Carpeta usually means:

• folder
• file
• sometimes binder depending on context

So en la carpeta means in the folder.

This is a very common use of en to indicate location:

• en la mesa = on the table / in the table’s location context
• en la caja = in the box
• en la carpeta = in the folder

Here it tells you where the copy was stored.

Y means and.

It connects the two completed actions:

• La destinataria firmó el aviso
• el remitente guardó una copia en la carpeta

A useful rule: y changes to e before words that begin with an i sound.

For example:

• padre e hijo = father and son
• España e Italia

But here, the next word is el, so it stays y:

• ... el aviso y el remitente ...

Yes, Spanish word order is somewhat flexible, though the original sentence is the most neutral and natural.

Original:

• La destinataria firmó el aviso y el remitente guardó una copia en la carpeta.

Possible variation:

• El remitente guardó una copia en la carpeta y la destinataria firmó el aviso.

That changes the focus/order of information, but not the basic meaning.

Within each clause, Spanish usually keeps a fairly straightforward order here:

• subject + verb + object

So the original sentence sounds natural and clear.

Yes. Spanish normally uses definite articles more often than English, and they must match the noun’s grammatical gender and number.

Here:

• la destinataria → feminine singular
• el aviso → masculine singular
• el remitente → masculine singular
• una copia → feminine singular, indefinite
• la carpeta → feminine singular

For English speakers, the key thing is not to assume noun gender from English. You have to learn each noun in Spanish with its article.

Then you would normally say:

• La destinataria firmó el aviso y la remitente guardó una copia en la carpeta.

Notice that remitente stays the same, but the article changes from el to la.

That is a common pattern with nouns like:

• el/la estudiante
• el/la cantante
• el/la gerente
• el/la remitente