Carlotta is the Italian form of Charlotte — from the Germanic karl (free man) — meaning "free woman." Carlotta of Mexico (1840-1927), born Princess Charlotte of Belgium, was the Empress of Mexico during the brief French-installed empire.
Carlotta is widely used in Italy.
Carlotta does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Carlotta reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.