I wonder why the wiki put this all under Commander Shepard's profile? I know they didn't put it anywhere else (yet) because I tried to find this several hundred pages ago from the wiki:
Fate
During the final battle for Earth, Shepard is gravely wounded in an attack by Harbinger. After reaching the Citadel and dealing with the Illusive Man, Shepard is greeted by the Catalyst - an ancient A.I. that controls the Reapers. The Catalyst explains to Shepard the purpose of the Reapers and their Cycle of destruction, and then states that Shepard has up to three options to end the war:
1.Destroy the Reapers: In this ending, Shepard shoots a key control panel, causing a massive explosion. Using the mass relays, the energy fired by the Crucible travels from relay to relay, causing all synthetics to be destroyed across the galaxy, including the Reapers, EDI and the geth. The mass relays, and the Citadel are badly damaged but eventually repaired. If the player's Effective Military Strength is high enough, Shepard is shown to have survived, taking a deep breath in a pile of rubble.
2.Control the Reapers: Shepard takes control of the Reapers, becoming the new Reaper master consciousness. The Reapers depart Earth in this scenario and the Citadel survives and the Reapers help rebuild the galaxy, including the mass relays. If Shepard is a Paragon, the Commander will "give the many hope for the future". If Shepard is a Renegade, the Commander will "provide the many with a powerful leader".
3.Synthesis: In this ending, Shepard jumps into the Crucible's energy beam, sacrificing their life. Shepard's sacrifice transforms all life in the galaxy into a new form of synthetic-organic life. The Reapers depart Earth and the mass relays and Citadel are damaged by the Crucible firing. The Reapers help rebuild the galaxy, including the mass relays, and share the knowledge of the civilizations they have harvested in the past.
4.Refusal: In this ending, Shepard refuses to choose any of the three possible options. The Catalyst acknowledges the Commander's decision and disappears leaving the Crucible unable to fire. The Reapers succeed in harvesting all advanced organic life throughout the galaxy as well allowing the cycle to continue.
Assuming Shepard chooses an option that activates the Crucible, then many years in the future, Commander Shepard has become a legendary figure known as "The Shepard". If Shepard does not activate the Crucible, another cycle learns of their actions through Glyph, and all that is known about "The Shepard" is what was stored in the archives left by Liara.
If Shepard chooses an option where he/she is killed, the epilogue shows the squad along with Joker, Cortez (if he survived) and Traynor. The squadmate Shepard was closest to places Shepard`s name above Anderson's on the memorial wall, and, if Shepard chose to merge organic and synthetic life, hugs EDI. If, however, Shepard chose to destroy the Reapers and managed to survive the Crucible's blast, the squadmate hesitates to put Shepard's name on the wall and instead smiles hopefully.