After death, Jedi travel to an ethereal place called the "Netherworld of the Force." The afterlife was first referenced in a draft of Return of the Jedi (via Wookieepedia), and it later made an appearance in Legends via 1984's Star Wars #92.
Luke Skywalker gave his father a Jedi funeral on Endor. Jedi funerals were given to Jedi who had perished and were subsequently cremated, provided their bodies were intact. Qui-Gon Jinn was known to have been given one, and later Anakin Skywalker was known to have been laid to rest in this way by his son on Endor.
Mustafar earned a horrific reputation throughout the galaxy, with Kanan once telling Hera Syndulla it was "where Jedi go to die." Audiences are more aware of the planet's history than most of the galaxy's citizens, but such an understanding of the Sith world is indicative of what people know about Mustafar.
Do all Jedi become one with the Force when they die?
While most Jedi would lose their bodily envelope and become one with the totality of the Force upon their death, some had learned a technique allowing them to retain their own identities separate from the Force for a time.
George Lucas Explains Padme's Death (NOT Palpatine)
How many Jedi actually survived?
According to Imperial Estimates in Star Wars Inside #87, only about 100 of the Jedi survived Order 66. Most were subsequently hunted down and killed in the years following the Great Jedi Purge.
The reason these Jedi fade from existence rather than leave a body is due to teachings learned by Qui-Gon Jinn. He died before being able to complete the training, so while he is able to manifest himself as a Force ghost, his physical body did not fade upon death.
After the end of the Galactic Civil War, Jedi Knight Luke Skywalker was the last Jedi left in the galaxy. His Jedi Master, Yoda, had died after securing his promise to pass on what he had learned.
Typically, Humans had an average lifespan of 100 to 120 standard years. Those who were keenly atuned to the Force, a ubiquitous and binding power that suffused the whole Known Universe, could live up to 200.
Nevertheless, most Jedi died. This included in the Jedi Temple, where almost everyone, including younglings, were killed by Vader and his clone forces.
However, some of the most powerful and ruthless Jedi Masters in the Star Wars universe include Mace Windu, Yoda, Obi-Wan Kenobi, Qui-Gon Jinn, Luke Skywalker, and Anakin Skywalker (prior to his turn to the dark side).
Fans loved to hate Darth Vader as one of the most powerful Jedi in the universe, but in the prequels, Anakin was just the most hated Jedi because of who he was.
The ceremonies -- which have been depicted in 'Game of Thrones' and 'Star Wars: Episode I - The Phantom Menace,' -- are a form of honoring the dead that is still widely practiced elsewhere, but is only legal in two sites in the United States, both of which are in Colorado and only one is public.
Jedi aren't typically sentimental, so it's rare they'd be buried with it, and the kyber crystal inside each lightsaber is said to be unique to that Jedi, so it's unusual that another Jedi would use a pre-owned lightsaber.
A Jedi was permitted to kill in self-defense - but only if there was no other option. To conquer aggression, even in combat, a Jedi must have explored every other option, including surrender, before resorting to using lethal force.
Some Jedi achieved immortality as Force spirits, their consciousness preserved in the Force. Every living being became one with the Force during the process of dying.
The role of a Jedi is one that lasts a lifetime, it is a career that only ever really ends when one becomes one with the Force. Regardless of age or physical condition, one is always a Jedi, and will always perform duties in that capacity.
Following Palpatine's final defeat and her own resurrection, Rey adopts the name Rey Skywalker to honor her mentors and their family legacy and renounce her lineage. As the last remaining Jedi, she makes it her mission to rebuild the Jedi Order.
While fans don't know the state of Grogu's well-being in the sequel trilogy, his ties to Mandalore might explain why Kylo Ren doesn't kill him. It's likely Grogu stays with Din Djarin and the Mandalorians, and never returns to embark on his training with Luke.
Although Solo was the last of the Skywalker bloodline, Rey assumed the name "Skywalker" to honor their memory, repudiating her own heritage as a Palpatine.
Qui-Gon: I cannot. My training was incomplete. As such, he can only ever materialize as a disembodied voice in the physical world. The other Jedi who have achieved oneness with the Force have disappeared upon death, such as Yoda, Obi-Wan, and Luke.
Jedi funerals occurred when a Jedi had died and was cremated. Exceptions to this funeral practice were made in times of war, when a body was left in an extreme environment, or in very rare cases when the Jedi used a technique to retain their identity after death, and therefore, physically disappear upon their death.
We are led to assume this as in TCW Qui-gon admits his training was incomplete. He could only appear on Mortis, anywhere else he could only be a disembodied voice.
