La firma electrónica acompaña al sello electrónico.

La is the feminine singular definite article, meaning the, and it goes with firma because firma is a feminine singular noun.

Al is a contraction of a + el:

• a = to or sometimes marks a relationship after certain verbs
• el = the (masculine singular)

So:

• la firma = the signature
• al sello = literally to the seal/stamp

In Spanish, a + el normally becomes al.

Because adjectives in Spanish usually agree in gender and number with the noun they describe.

• firma is feminine singular, so the adjective is electrónica
• sello is masculine singular, so the adjective is electrónico

This is a very common pattern:

• documento oficial
• copia oficial
• firma electrónica
• sello electrónico

In Spanish, adjectives often come after the noun, especially when they are descriptive or classificatory.

So Spanish prefers:

• firma electrónica
• sello electrónico

rather than putting the adjective first.

This is different from English, where adjectives usually come before the noun:

• electronic signature
• electronic seal

Acompaña is the third-person singular present tense of acompañar.

So it means:

• accompanies
• goes with
• comes together with

In this sentence, the subject is La firma electrónica, which is singular, so the verb is also singular:

• La firma electrónica acompaña...

Other forms of the same verb:

• yo acompaño = I accompany
• tú acompañas = you accompany
• él/ella acompaña = he/she accompanies

The verb acompañar commonly takes the preposition a when the thing or person being accompanied is introduced.

So:

• acompañar a alguien
• acompañar al documento
• acompañar al sello electrónico

Because sello is masculine singular and uses el, a + el becomes al.

This is something you often just learn as part of the verb’s pattern in use.

Yes, in practical terms, it is the object of the verb, but it appears with the preposition a because Spanish sometimes uses a with certain verbs or with animate/direct objects.

Here, acompañar is often used with a, so you get:

• acompaña al sello electrónico

For a learner, the most useful thing is to remember the chunk:

• acompañar a

The written accent mark shows where the stress goes.

• electrónica → stress on nó
• electrónico → stress on nó

So roughly:

• e-lek-TRÓ-ni-ka
• e-lek-TRÓ-ni-ko

Also:

• c before a, o, u is a hard k sound
• in Spain, the c in electrónica is still k because it comes before a

Although firma looks similar to English firm, in Spanish firma means signature.

This is a good example of a false friend risk: words that look familiar but do not mean exactly what you might first guess.

Related words:

• firmar = to sign
• la firma = the signature

In some contexts, firma can also refer to a company/firm, but in a sentence like this, it usually means signature.

They are different kinds of official validation.

• firma = signature
• sello = seal or stamp

So in administrative or legal language:

• firma electrónica = electronic signature
• sello electrónico = electronic seal

Even if the exact legal difference depends on context, grammatically they are two different nouns:

• la firma
• el sello

Yes, that is grammatically correct, but it changes the focus and possibly the meaning.

Original:

• La firma electrónica acompaña al sello electrónico.

Alternative:

• El sello electrónico acompaña a la firma electrónica.

Both are structurally correct:

• subject + verb + a
  • object

But the subject changes, so the sentence now says that the electronic seal accompanies the electronic signature, not the other way round.

That is the most neutral Spanish word order:

• Subject + Verb + Complement/Object

So:

• La firma electrónica = subject
• acompaña = verb
• al sello electrónico = complement/object

Spanish word order can be more flexible than English, but this version is the standard, clear order.

Usually not in a sentence like this.

Spanish often uses definite articles more regularly than English does, especially with formal or technical nouns.

So the natural form is:

• La firma electrónica acompaña al sello electrónico.

Leaving them out:

• Firma electrónica acompaña a sello electrónico

would sound unnatural or incomplete in normal Spanish.

Yes, it sounds formal, administrative, or legal/technical.

Words like:

• firma electrónica
• sello electrónico

are common in official documents, digital authentication, and legal or institutional contexts.

A learner should notice that the grammar is normal everyday Spanish, but the vocabulary belongs to a more formal register.