The passport itself never travels
Nobody stamps a passport. The book stays in your pocket, and a reader abroad who asks for a stamped passport really wants a sealed copy of its pages. That sealed copy is a separate sheet. A clerk holds the copy against the book in front of you, then signs and seals the sheet as a true likeness of what they saw.
An apostille is the state's certificate that a signature and a seal are genuine. It lets a reader in a Hague country act on your sheet without writing to a consulate first. To apostille a passport copy in Italy you need that sealed sheet, then a tax stamp, then the state desk. Italy has been inside the Hague network since 1978, so the last part moves fast.
Getting the sealed true copy made
Readers who ask how you apostille a passport copy often begin at the wrong counter. Take the book and a plain photocopy to a municipal office and ask for a copia conforme, which is the local wording for a certified true copy. The clerk checks each page against the book, writes the wording and signs it. The book leaves with you; only the sealed sheet goes on.
Say at that counter that the sheet is bound for another country. Some clerks then use the fuller wording a foreign reader expects, naming the holder and how many pages were copied. Ask for two sealed sheets while you are standing there, because a second reader will not take a photocopy of the first. Every sealed sheet counts as its own document later.
Which desk adds the stamp
Once the copy is sealed the paper is an administrative act, so the Prefettura is the desk that stamps it. That office keeps the specimens of the municipal clerks in its province and matches the hand on your sheet against them. Judicial and notarial acts travel another road and are signed by the Procura della Repubblica at the court. Ask the municipal office which of the two roads your sealed sheet takes before you queue.
Which pages to copy
Copy only what the reader named. Most want the page with the photograph, the number and the dates, and nothing beyond that. Some banks ask for the signature page as well, and a few want every visa page in the book. Read their list first, because the clerk seals the pages you brought, and adding one later means a fresh sheet and a fresh queue.
Cost of the stamp
The apostille cost for a passport copy in Catania is a €16 tax stamp per document, and some papers are exempt by law. Buy the stamp at a tobacconist first, since the desk holds no card reader. Two sealed sheets mean two stamps, so settle the count before you pay for anything. No waiting time is published for this desk, so allow a spare day.
Legalisation of a passport copy in Catania is the older and longer route, used where the reader's country stays outside the Hague network. A consulate adds its own signature after the state has, and each keeps a list of extras. Whether your destination needs that chain depends on where the sheet is going, so ask the receiving authority in writing.
Banks, company files and other readers
Most people apostille a passport copy in Catania for money or company work. A bank abroad opening an account wants proof of who signed the forms. A registry wants the identity page behind a director's name. A lawyer abroad wants it filed with the company papers. In each case the reader leans on the seal rather than on your word.
One warning is worth reading twice. The stamp vouches for the clerk who sealed the copy, not for the book and not for you. If the passport is close to its end date, a reader may turn the file down even with a perfect stamp on the sheet. Check the date printed in the book before you spend a euro on this errand.