La mesa electoral está aquí.

Because mesa is a feminine noun in Spanish, so it takes the feminine singular article la. The article agrees with the noun, not with the English meaning.

• la mesa
• la mesa electoral

Not all Spanish adjectives have different masculine and feminine forms. Adjectives ending in -al usually stay the same for both genders.

So you get:

• el proceso electoral
• la mesa electoral

In both cases, electoral stays electoral.

Because Spanish normally uses estar for location.

• La mesa electoral está aquí = it is located here

Using ser would sound wrong in this sentence. Ser is generally used for identity, classification, origin, and similar ideas, not for where something is.

So:

• Está aquí = is here / is located here
• Es aquí is not the normal way to say this

In Spanish, many adjectives come after the noun, especially when they classify or describe the type of thing something is.

So:

• mesa electoral = an election-related table/board

This is more natural in Spanish than putting the adjective first. English often puts adjectives before nouns, but Spanish very often puts them after.

Yes. That is perfectly natural.

Both sentences are correct:

• La mesa electoral está aquí.
• Aquí está la mesa electoral.

The difference is mainly emphasis:

• La mesa electoral está aquí focuses first on the polling table/board
• Aquí está la mesa electoral focuses first on here

Usually, yes. In this sentence, la sounds natural because you are talking about a specific, identifiable mesa electoral.

Without the article, Mesa electoral está aquí would sound incomplete or unnatural in normal speech. You might only see article-less language in headlines, signs, or note-style writing.

The accent mark shows which syllable is stressed.

• está → stress on the second syllable: es-TÁ
• aquí → stress on the second syllable: a-QUÍ

In está, the accent also helps distinguish it from esta, which can mean this (feminine).

• esta mesa = this table
• está aquí = is here

They are similar, and both can mean here, but in Spain aquí is the more standard everyday choice. Acá is more common in many parts of Latin America.

So for Spanish from Spain, aquí is the safest and most natural option here.

A rough English-friendly pronunciation is:

lah MEH-sah eh-lek-toh-RAL es-TA ah-KEE

A few useful details:

• mesa = MEH-sa
• electoral = eh-lek-toh-RAL
• está = es-TA
• aquí = a-KEE

In Spain, the r in electoral is a light tapped r, not a strong English r.