La copia maestra tiene una copia de seguridad.

In Spanish, most descriptive adjectives usually come after the noun, not before it.

So:

• la copia maestra = the master copy

Here maestra describes what kind of copy it is. Putting the adjective after the noun is the normal pattern.

If you said la maestra copia, it would sound unnatural in standard Spanish.

Because it agrees with copia, which is a feminine singular noun.

• la copia
• maestra

In Spanish, adjectives normally match the noun in gender and number:

• el libro rojo
• la casa roja
• las copias maestras

Since copia is feminine singular, the adjective must also be feminine singular: maestra.

Una means a / one, and here it introduces a backup copy as a singular countable thing.

So:

• tiene una copia de seguridad = it has a backup copy

You could sometimes omit the article in certain contexts, but that would change the feel of the sentence. With una, it clearly means it has one backup copy / a backup copy.

Yes, effectively it works like an adjective phrase.

• copia = copy
• de seguridad = of safety / for security

Together, copia de seguridad is the standard Spanish expression for backup copy or simply backup.

This is very common in Spanish: instead of using a single adjective, Spanish often uses noun + de + noun.

Examples:

• gafas de sol = sunglasses
• cinturón de seguridad = seat belt
• copia de seguridad = backup copy

So even though seguridad is a noun, the whole phrase describes what kind of copy it is.

Tiene is the third-person singular form of tener in the present tense.

• tener = to have
• tiene = he/she/it has

The subject is la copia maestra, which is singular, so the verb must also be singular:

• La copia maestra tiene...

Even though English uses it has, Spanish often just uses the noun itself instead of a separate pronoun.

Not with the same meaning.

• tiene = has
• hay = there is / there are

So:

• La copia maestra tiene una copia de seguridad = The master copy has a backup copy
• Hay una copia de seguridad = There is a backup copy

These are different ideas.
Tiene shows possession or association.
Hay only says that something exists.

Yes, copia de seguridad is a very common and standard expression, including in Spain.

Depending on context, you may also hear:

• backup in tech speech, especially informally
• copia de respaldo in some regions or more technical/international usage

But for standard Spain Spanish, copia de seguridad is completely natural and very common.

Yes, you can, but it changes the nuance slightly.

• tiene una copia de seguridad = it has a backup copy
• tiene copia de seguridad = it has backup / it has a backup system in place

Without una, the phrase can sound a bit more general or abstract, as if you are talking about the existence of backup protection rather than highlighting one specific copy.

Both are possible, but una copia de seguridad is clearer for learners and more concrete.

A careful pronunciation in standard Peninsular Spanish would be approximately:

la KO-pya ma-ES-tra TYE-ne OO-na KO-pya de se-gu-ri-DAD

A few useful points:

• copia: the c before o sounds like k
• maestra: the stress is on -es-
• tiene: pronounced roughly TYE-ne
• seguridad: the stress is on the last syllable, -dad

In standard Spain Spanish:

• c before e/i is often pronounced like the th in thin
• but in this sentence, the c in copia is before o, so it is just a k sound

It would be:

Las copias maestras tienen copias de seguridad.

Changes:

• la → las
• copia → copias
• maestra → maestras
• tiene → tienen
• una copia → copias or unas copias, depending on meaning

This shows how articles, nouns, adjectives, and verbs all change to match number in Spanish.