Samuel L. Jackson’s Mace Windu was one of the more memorable Jedi from the Star Wars Prequel Trilogy. He was renowned as an exceptionally skilled warrior, became a Jedi General and personally participated in some of the biggest battles of the Clone Wars. But despite his wisdom and skill, he didn’t see Darth Sidious’ manipulations until it was too late. Windu valiantly tried to take down the Sith Lord, but Anakin Skywalker intervened just as he was about to strike him down. In the ensuing struggle, Windu’s hand was chopped off, he was electrocuted with Force Lightning and then blasted out of a window.
It’s at this point that things get fuzzy. As far as the ongoing Star Wars saga is concerned, this is how Mace Windu died. However, we don’t actually see him die and it’s definitely possible that a powerful Jedi could survive being thrown out of a tall building (even while injured). This has led to theories that Windu is alive, and there were even those who claimed he eventually became Supreme Leader Snoke. Personally, I doubt that Windu lived as he doesn’t seem like the type to just go into hiding like Yoda and Obi-Wan did.
After the plunge, the only evidence of Mace Windu that turned up was his distinctive purple lightsaber, found by a scavenger on the lower levels of Coruscant. So, what happened to his body? Well, you could argue that he became one with the Force and faded from existence, though I doubt his traditionalist Jedi philosophy and the way he died would allow that.
The way I see it there are two possibilities. One is that his body was discovered and unceremoniously disposed of. After all, in the wake of Order 66, it’s unlikely they’d be holding ceremonies to honor dead Jedi. The other is that he landed in such a place that they never actually found his body. Perhaps the residents of some poor Coruscant apartment block had to put up with a really bad smell for a few weeks? After all, it is a very densely constructed city.
Whatever happened to his body, we know that Windu’s spirit survived as we heard him urging Rey on during the ‘Jedi chorus’ in the finale of Star Wars: The Rise of Skywalker. Maybe it’s best not to worry about it though and just keep Yoda’s teachings in mind: “Luminous beings are we, not this crude matter.”