Moons are the natural satellites of a planet and these celestial bodies orbit around the planet. The name of Earth's natural satellite is Moon. Similarly, many of the other planets of our solar system also have moon/s. Here is a list of number of moons of each planet in our solar system:
Mercury: 0 moons
Venus: 0 moons
Earth: 1 moon
Mars: 2 moons
Jupiter: 67 moons* (including 17 provisional moons)
Saturn: 62 moons* (including 9 provisional moons)
Uranus: 27 moons
Neptune: 14 moons* (including 1 provisional moon)
Thus, Jupiter and Saturn have the largest number of moons, as compared to other planets of our solar system.
The 4 most famous moons of Jupiter are known as Io, Ganymede, Callisto and Europa. The most famous moon of Saturn is known as Titan.
Note that the number of moons of each planet may change (in future) depending upon the observation of newer celestial bodies with better technology in the future.
Hope this helps.