When you pay someone to perform a service for you—like styling your hair or fixing your shoes—English uses "to have [something] done." Italian uses a special causative construction: the reflexive verb farsi followed immediately by an infinitive.
The Causative Farsi
Conjugate farsi like a normal reflexive verb (mi faccio, ti fai, etc.) and place the action being performed in the infinitive.
| Today I am having my hair styled. | Oggi mi faccio fare la piega. |
To specify the professional performing the service, introduce them with the preposition da (by) combined with the definite article (dal sarto, dall'estetista).
| I have the hem shortened by the tailor. | Mi faccio accorciare l'orlo dal sarto. |
| You have your nails done by the beautician. | Ti fai sistemare le unghie dall'estetista. |
Farsi in the Past Tense
Because this construction is built on a reflexive verb, it takes the auxiliary verb essere (to be) in the passato prossimo.
The past participle (fatto) agrees in gender and number with the subject (fatto, fatta, fatti, fatte). The infinitive verb that follows remains unchanged.
| Yesterday I had my hair dyed. | Ieri mi sono fatta tingere i capelli. |
Notice how a female speaker says mi sono fatta, while a male subject uses si è fatto.
| He had the soles replaced by the cobbler. | Lui si è fatto cambiare le suole dal calzolaio. |
For plural subjects, the participle becomes fatti (or fatte for a strictly feminine group).
| We had the pants shortened within the week. | Ci siamo fatti accorciare i pantaloni entro la settimana. |