What will happen at the end of the sun's life?
When the sun runs out of hydrogen to fuse, it will start fusing helium into heavier and become a red giant. After it has run out of helium, it will expel its planetary nebula and become a white dwarf.
Our sun is currently a main-sequence star of relatively common occurrence and is fusing hydrogen into helium, producing a massive amount of energy every second.
Scientists estimate that the sun has about 5 billion years left on the main sequence- after which our sun will become a red giant-engulfing the inner planets, including Earth. However, it is not massive enough to become a supergiant, nor collapsing into a black hole- but will instead become a white dwarf after the red giant runs out of helium to fuse- but this will take approximately another 10 billion years before occurring.