Legalization is the process of certification of a specific document. This is done affixing a stamp or sticker on the document itself or on a separate certifying paper, so that the specific document is officially recognized.
If the country that issued the document has signed the Hague Convention of 5th October 1961, then the legalization is done by mean of a procedure called Apostille; otherwise, the document must be legalized also by the Embassy/Consulate of the country of destination located in the country of issue.
ItalianPapers can request in your behalf the Apostille and/or the Consular Legalization for documents issued by Italian authorities or by foreign embassies in Italy.