A large number of experimental studies have confirmed that water (as ice) is present in multiple locations on the Moon. A 2010 study from NASA estimated that there are at least 600 million metric tonnes of ice around the Moon's North pole alone. (ref.)

It's discovery is of particular significance for future exploratory Moon missions, both as a source of usable raw water, and as a source for hydrogen, as fuel, via electrolysis.

Its origin(s), however, remain unclear, though there a number of theories,

Though the presence and persistence of water on the lunar surface have been documented, the origin, which is multifaceted and complicated, remains unexplained. Lunar water likely has many sources, including primordial water (Boyce et al. 2010; McCubbin et al. 2010; Hui et al. 2013; Robinson et al. 2016), volatile rich cometary and meteoritic delivery (Greenwood et al. 2011), synthesized and released during an impact event (Daly & Schultz 2018; Stopar et al. 2018; Zhu et al. 2019; Huang et al. 2021), and solar wind proton implantation (Zeller et al. 1966; Schaible & Baragiola 2014; McLain et al. 2021; Xu et al. 2022). The relative contribution of each of these sources is not known."

Source : The Planetary Science Journal, Volume 5, Number 8

Also see : Earth's waterplugin-autotooltip__plain plugin-autotooltip_bigWater - its origin

One obvious difference between Earth and other planets in the Solar System is that it's 70% covered in liquid water. There are at least five major (and very different) theories proposing the origins of such a large volume of water (estimated at around 1.3 billion cubic kilometres).