Fyrirtækið sendir fulltrúann.

Because Icelandic usually puts the at the end of the noun instead of using a separate word.

• fyrirtæki = company
• fyrirtækið = the company

Here -ið is the definite article for a neuter singular noun in the nominative.

Fulltrúi is the dictionary form, meaning representative.

In this sentence, the representative is the direct object of sendir, so the noun has to be in the accusative case. That changes the form:

• fulltrúi = nominative singular indefinite
• fulltrúa = accusative singular indefinite
• fulltrúann = accusative singular definite, the representative

So fulltrúann is the correct object form here.

Because fulltrúinn is the nominative definite form, which is normally used for the subject:

• fulltrúinn = the representative as subject
• fulltrúann = the representative as object

In Fyrirtækið sendir fulltrúann, the company is doing the action, so fyrirtækið is the subject, and fulltrúann is the object.

Sendir is the present tense of the verb senda, meaning to send.

Relevant forms are:

• ég sendi = I send
• þú sendir = you send
• hann / hún / það sendir = he / she / it sends

Since fyrirtækið is a third-person singular subject (it, grammatically), sendir is the right form.

Yes, very often it can.

Icelandic present tense can cover both:

• The company sends the representative
• The company is sending the representative

Usually the exact meaning depends on context.

They are:

• fyrirtæki — noun, neuter
• fulltrúi — noun, masculine
• senda — verb, to send

The different endings in the sentence come from gender, case, number, and definiteness.

It is attached to the nouns themselves.

So instead of a separate word like English the, Icelandic often uses a suffixed article:

• fyrirtækið = the company
• fulltrúann = the representative

That is one of the first big differences English speakers notice in Icelandic.

No, this is the normal, neutral word order:

• Fyrirtækið = subject
• sendir = verb
• fulltrúann = object

So it follows a basic subject–verb–object pattern, much like English.

Icelandic word order can be more flexible than English, but this sentence is the straightforward default.

Because the noun itself is the subject, and the verb form already matches it.

Fyrirtækið is grammatically third-person singular neuter, so Icelandic simply uses the noun with the correct verb:

• Fyrirtækið sendir ... = The company sends ...

If you replaced the noun with a pronoun, it would be það = it.

You would remove the suffixed definite article:

• Fyrirtæki sendir fulltrúa.

That means A company sends a representative or Company sends representative, depending on context.

In practice, English articles and Icelandic article usage do not always match perfectly, but that is the basic contrast.