Leave the parchment where it is
Your diploma was handed to you as a single printed sheet, sometimes on heavy paper with a raised seal. It cannot be replaced if it is lost in the post or marked by a counter clerk. Nobody in this chain needs that sheet. What every desk wants is a copy signed by the school, or the school's own substitute certificate, and those can be reissued.
What to ask your old school for
Go to the segreteria, the school office, and ask for a certified copy of the diploma or the certificato sostitutivo del diploma. Say out loud that it is going abroad. The head of the school signs it, and that signature is what later desks compare. Bring your identity papers and the year you finished, because older files sit in a store room and take a day or two to reach the counter.
This is where knowing how to legalize a High School Diploma saves a wasted week: the copy must carry a wet signature and the school stamp. A photocopy of your parchment, even a clear one, has no signature of its own. The state office has nothing to match it against, so it will hand the sheet straight back to you.
When the schools office signs instead
Some schools have closed or merged over the years. In that case the papers pass to the provincial schools office, which issues the certificate in the school's place and signs it with its own officer. The route afterwards does not change. Tell us which body signed and we check that its officer is one the state desk can match.
The Prefettura stage
A school is a public body, so its papers are administrative ones. Embassy legalization of a High School Diploma in Palermo therefore starts at the Prefettura (Prefecture), which vouches for signatures of state and local staff. Court and notary papers go elsewhere, to the Procura della Repubblica, and that road is not yours. A €16 tax stamp goes on the file at this counter.
The consulate stage and its fee
Consular legalization of a High School Diploma in Italy is the closing move. The mission serving your destination checks the state stamp is there, then adds its own mark and its own fee. Ask us to get that tariff in writing first, since a few missions charge by the sheet and a diploma file often runs to several. Count on 10–15 business days, or 3–5 business days when we rush it.
Whether that mission stamp is wanted at all depends on the country your file is going to, so ask the office that will read it and keep the answer. A few will take the state stamp on its own. Others will not look at the file without the mission mark beside it. We build the bundle around whatever they tell you.
Marks, subjects and the second sheet
A diploma says you finished; it rarely says what you studied. Universities abroad usually want a second sheet listing subjects and marks, which the school prints separately. That second sheet needs its own stamps, so order both at the same visit and let them travel together. Ask the receiving office, in writing, which language it wants them in before you pay for any translation.
Where a stamped school paper is used
Most people legalize a High School Diploma in Palermo to enrol at a university abroad. Others need it for a student visa, or to have a trade skill weighed up by a licensing board. Employers ask for it too, though usually later in a hiring file. Embassy attestation of a High School Diploma in Palermo is what turns a Sicilian school sheet into a paper a foreign registrar will file.