Where is passport control?
con-TROL-lo — double 'l', stress on second syllable. 'Passaporti' is pas-sa-POR-ti.
After check-in, when heading to the security and boarding area, especially on international flights.
'Controllo passaporti' is the standard Italian term for passport control or immigration. 'Dov'è' (where is) works for asking about any location. For Schengen flights within Europe, you may not need passport control at all, only security screening.
Dove si trova la dogana?
Where is customs?
'Dogana' is customs — used on arrival from non-EU countries
Dove sono i controlli di sicurezza?
Where are the security checks?
Security screening before the gate
Da che parte si va per i voli internazionali?
Which way for international flights?
Broader directional question at a large hub
Italy is part of the Schengen Area, so passport control is only required for non-EU travelers or when flying to/from non-Schengen countries. EU citizens use the faster EU/EEA lanes. Non-EU visitors must queue at the 'Tutti i passaporti' lane.