What Happens When We Die?

The Encyclopedia of Jewish Myth, Magic, and Mysticism;
Rabbi Geoffrey Dennis, p. 65
The soul of the dead escapes through the mouth and at that moment its voice can be heard from one end of the universe to the other (Gen. R. 6:7). The windows in the place where a corpse rests should be opened to allow the spirit to move freely. Based on Job 14:22, the Rabbis teach that the soul remains conscious, some say until the interment, while others claim the dead can hear the living until the final decomposition of the body (Shab. 152b). Some teach that the disoriented soul hovers about the body for three days (others claimed seven) seeking to reenter it (Lev. R. 18:1; PdRE 34). According to the Zohar, the soul of the newly dead wanders between its earthly residence and its grave (I: 226b).
Since the souls of the dead stay close to their bodies until their transition to Eden, ghosts are mostly limited to the confines of the cemetery (Shab. 152b). The soul's separation from the body is a painful one, a process called chibbut ha-kever, "the torment of the grave." One Sage asserts that worms feel like needles to the dead (Ber. 18b). This tradition is based on the belief that the grave itself is atonement for the sins committed in life (Ket. 111a).
Kabbalists who taught the doctrine of reincarnation believed that the souls of the dead, or at least parts of a soul, transmigrate from one living body to another, and the souls of the disturbed dead can possess the body of a living being. The souls of the righteous can be temporarily recalled to this world to help the living (Kav v'Yasher; Sha'ar ha-Gilgulim).
Despite the belief in moral accountability through death, because Jews have not been burdened with the fear of "eternal damnation," Jewish teachings have generally viewed death with great equanimity. The Kotzker Rebbe compared death to "moving from one home to another." [Rabbi Abraham Joshua] Heschel spoke of it as a "homecoming."

The Encyclopedia of Jewish Myth, Magic, and Mysticism;
Rabbi Geoffrey Dennis, p. 83-84
Jewish tradition has always taught that mortals have, or will have, a continued existence after death. Isaiah 25, the prophet promises that a time will come when death will disappear entirely. The Bible describes an underworld realm of the dead called Sheol (grave), where souls dwell in dark silence. In Greco-Roman times the first descriptions of a heavenly afterlife start to appear in Jewish literature.
In rabbinic imagination, Torah is synonymous with the Tree of Life, which was lost as a consequence of the sin of Adam and Eve. Thus, the giving of the Torah at Sinai restores the possibility of human immortality. In addition to this, because of their immersion in Torah, saintly men are also immune from most (but not all) forms of death (Shab. 55b). The souls of the righteous are escorted to their reward by three companies of angels, each uttering their own message of comfort. For the wicked, three myriads of destructive angels serve as escort, quoting Scriptural verses of reproach (Ket. 104a).
The quality of the afterlife an individual has is based on moral criteria: the righteous will enjoy eternal favor and ease, the wicked face annihilation, and those of us in between, the beinonim, must face trials and punishment for our sins, to ensure that in the end we will enjoy recon- ciliation with God. Descriptions of what eternal life entails vary across Jewish tradition and sources.
The belief in resurrection, the bodily restoration of the dead in the End of Days, is based on Ezekiel 37, Daniel 12:2, and Isaiah 65:17. Resurrection has been the predominant way that Jews understand and envision the afterlife (II Maccabees, Talmud, and the Gevurot prayer of the daily liturgy). Exceptionally righteous figures, however, can be translated directly into heaven, where they become celestial luminaries and angels (I Enoch 102). Examples of such individuals include Enoch, Elijah, and Serach bat Asher.
Under Greek influence, there also arises a belief in a disembodied eternal existence (Jubilees 23; I Enoch 103-4; IV Maccabees 14). Later rabbinic tradition eventually reconciles these competing traditions of bodily resurrection and disembodied heavenly existence.
Finally, Jewish mysticism teaches that there is a mechanism involving transmigration of souls that is also part of the journey towards eternal life.

Central Conference of American Rabbis: A Statement of Principles for Reform Judaism, 1999
We trust in our tradition's promise that, although God created us as finite beings, the spirit within us is eternal.
Commentary on “A Statement of Principles, 1999”
As in the case of God’s role in time of crisis, the culture in which we live no longer presumes that immortality is unscientific, irrational or unbelievable. Reform Jews are now liberated from the constraints of a religion based solely on rationalism, or a limited understanding of science. But this principle says, "We trust in our tradition’s promise...." There is nothing new in the belief in the eternality of the spirit. "Our tradition" here is best understood both as the broad Jewish tradition and the stated if not always accepted Reform tradition. The Books of Ezekiel (37:1-14) and Daniel (12:2) suggest the possibility of a spiritual life beyond death, and the second prayer in the Amidah, the Gevurot, speaks of God’s "keeping faith with those who sleep in the dust," echoing the passage from Daniel. An explicit belief in the soul’s immortality entered Judaism under the influence of the neo-Platonist Philo in the third century BCE.
Regardless of what you may have heard, the promise of eternal life of the spirit is part and parcel of Reform Judaism. The reading or chanting at funerals of the Eil Malei Rachamim which is wholly about eternal life; the affirmation of chayei olam (eternal life) in the Torah blessings; the various meditations before the kaddish in all our movement’s prayer books – all of these are witness to Reform Judaism’s continuing affirmation of eternal life. In a movement where adapting and editing, not to mention deleting, "traditional" prayers is a given, the retention of such elements tells us that the idea of eternal life has "an eternal life" in our movement.
Further, "We trust in our tradition’s promise" is a statement of comfort and assurance. The Bible promises, "I shall not die but live" (Psalms 118:17), and the Reform prayer book tells us, "There is something of us that can never die."
This principle, although in one sense a restatement of that which all three previous platforms affirmed, marks a great change because of the changed nature of the Reform Jewish community and its newly acknowledged needs. Most contemporary Reform Jews do not feel that their intellectual and scientific credentials are at issue. The religious issue is meaning in life and hope after life, not the need to make religion subservient to culture, science or some form of reason.