L'offerta di lavoro include la lettera di assunzione.

Because offerta starts with a vowel, and Italian usually drops the final vowel of la before another vowel.

So:

• la offerta → l'offerta

This is called elision. You will see it very often:

• l'amico
• l'idea
• l'acqua

The apostrophe shows that a vowel was dropped.

In Italian, noun + di + noun is a very common way to make expressions like:

• job offer → offerta di lavoro
• hiring letter / letter of employment → lettera di assunzione

Here, di lavoro and di assunzione are acting like classifiers: they tell you what kind of offer or letter it is.

So Italian normally says:

• offerta di lavoro
• lettera di assunzione

not:

• offerta del lavoro
• lettera dell'assunzione

Those versions would usually sound more specific or would mean something different.

Literally, yes, it is built that way. But in normal English, the natural translation is job offer.

This is very common in Italian: the structure may look more literal than the most natural English translation.

So:

• offerta di lavoro = job offer
• not necessarily a word-for-word offer of work in natural English

Because include is the Italian verb form, not the English one.

The infinitive is includere = to include.

In the present tense:

• io includo = I include
• tu includi = you include
• lui/lei include = he/she includes

So in the sentence:

• L'offerta di lavoro include la lettera di assunzione

include means includes.

It only looks familiar because it is very close to the English word.

It is pronounced roughly een-KLOO-deh.

A few useful points:

• the stress is on clu
• the final e is pronounced
• it is not pronounced like the English verb include

So try to say all three syllables clearly:

in-clu-de

Here, assunzione means hiring or employment.

So lettera di assunzione is a letter connected with hiring someone for a job.

It comes from the verb assumere, which in job contexts means to hire.

Be careful: assumere can look like the English verb assume, but in many contexts it does not mean the same thing. In work-related language, it often means:

• assumere qualcuno = to hire someone

So:

• assunzione = hiring / recruitment / employment
• lettera di assunzione = hiring letter / employment letter

Because la refers to a specific letter, not just any letter.

• la lettera di assunzione = the employment letter
• una lettera di assunzione = an employment letter

Using la suggests that this letter is understood as a definite document included in the offer.

Yes, it works as a standard noun phrase in Italian.

Italian often uses this pattern:

• noun + di + noun

For example:

• carta di credito = credit card
• sala da pranzo = dining room
• offerta di lavoro = job offer
• lettera di assunzione = employment letter

So lettera di assunzione is a normal, idiomatic way to say this kind of document.

Yes, you may sometimes see d'assunzione instead of di assunzione.

That is another case of elision:

• di assunzione → d'assunzione

Both can be correct, but di assunzione is very clear and straightforward for learners. The sentence you were given is perfectly natural.

Yes. The word order is very standard:

• L'offerta di lavoro = subject
• include = verb
• la lettera di assunzione = object

So it follows the basic subject–verb–object order, just like English:

• The job offer includes the employment letter

That makes this sentence quite easy structurally, even if some of the noun phrases are new.

It would become:

• Le offerte di lavoro includono le lettere di assunzione.

Changes:

• l'offerta → le offerte
• include → includono
• la lettera → le lettere

This is a useful way to notice agreement:

• singular subject → include
• plural subject → includono