The "Italian hitch" is the European name (particularly common in UK, Italian, German, and French climbing literature) for what is called the Munter hitch in American climbing. The two terms refer to the same knot — a friction hitch tied on a pear-shaped carabiner that allows controlled rope feed in either direction without a belay device.
Why two names? Werner Munter, the Swiss instructor who popularised the knot in 1970s climbing courses, called it simply the "halbmastwurf" (half-clove hitch in German). When the technique reached American climbing instruction it was credited to Munter and became the "Munter hitch." European literature often retained the older "Italian hitch" name (used by alpinists for decades before Munter codified the technique). The knot is the same; only the name varies by climbing tradition.
For full instructions on tying and using this knot, see our Munter hitch page — same technique, same applications, same tips. The two names are interchangeable in modern climbing usage.