How do i apply visa to Italy for 5 days?visitting friend in the Embassy of Vietnam to Italy

You should apply for an Italian visa from the Embassy of the Republic of Italy in Beijing. The required documents are such as your valid passport, visa application form, recent-taken photo, etc. You may call the embassy directly to get the accurate details.

If for private affairs, I'm afraid you have to apply for an ordinary passport to apply for the visa. Anyway, all depend on the Italy embassy.