Learn Italian: Oggi offrono il caffè. - Today they are offering coffee.

Offrono comes from the verb offrire (to offer), which is a regular -ire verb. To say "they" do something, we remove the -ire ending and add -ono. So, offrire becomes offrono.

Where is the word for "they" in the Italian sentence?

Italian usually drops subject pronouns like loro (they). The -ono ending on offrono already tells us exactly who is offering, so adding loro isn't necessary.

The translation says "they are offering", but doesn't offrono mean "they offer"?

It means both! In Italian, the present tense covers both general habits ("they offer coffee every day") and things happening right now ("they are offering coffee today"). You do not need a separate "-ing" form here.

Why is there an il before caffè if the English translation just says "coffee"?

In English, we often drop "the" when talking about things in general. Italian prefers to keep the definite article (il) even for general categories, though it could also mean they are offering a specific round of coffee.