Most of the verbs, such as parlare(to speak), sapere(to know), finire(to finish), are conjugated along with ‘avere’, while some other verbs, such as partie(to live), are conjugated along with ‘essere’. Hence we must learn the type of verbs.
We simply have to add -ato, -uto, -ito to the stem of verbs, depending on verb types. If verbs are in infinitive ends with -are, then just add -ato, add endings -uto to verbs that have an ending as -are, and lastly add -ito to the verbs ending with their infinitives –ire
Some verbs have the past participles with verb ‘avere’, while the other verbs that are mostly motion verbs have their past participles with verb ‘essere’.
Verbs that go with the verb ‘avere’ don’t have to go with factors such as number and gender. Keep in mind to form past participles with the verbs that conjugate along with ‘essere’, the gender and number factors matter, but it’s not the same with ‘avere’.