You've already seen that Italian uses a special verb form to say would, like penserei or offriresti.
Now we'll have a look at how to say things were possible in the past, like I would have called or you would have believed.
First, use the would form of avere that matches who you're talking about. Then change the next verb ending to ‑ato, ‑uto, or ‑ito.
Usually, you'll use ‑ato for verbs that end in ‑are, ‑uto for ‑ere verbs, and ‑ito for ‑ire verbs.
You've already seen how to say things like io avrei lavorato, which means I would have worked.
But for some verbs that talk about motion (like venire and andare), you'll use essere instead of avere.
Remember that verbs that use avere always end in ‑o (‑ato, ‑uto, or ‑ito), while verbs that use essere have different endings (‑o, ‑a, ‑i, or ‑e) depending on gender and whether you're talking about one person or multiple people.