Stars have a long lifetime, way too long for us to observe a single star's life cycle. Instead we study stars at different periods in their lives and build a picture of it.
On a dark night you might notice bands of darkness scattered along the Milky Way. It is vast clouds of gas and dust that are only visible when they block out the light from more distant stars. These giant clouds previde the raw material needed to make new stars.
If you look Orion's sword through bioculars, the middle star will appear misty. A telescope will show a cloud of gas brightly lit by a group of bright blue stars. These are the latest in a series to be born from the gas permeating the sky in Orion. Their formation was perhaps triggered by a star from an earlier generation has exploded as a supernova. It probably happened within the last few million years.
A stars lifetime depends largely on how massive it is. The more mass it gains, the closer it gets to its ultimate fate as a white dwarf, neutron star, or even black hole.
Once our Sun becomes a red giant, it will live about a billion years. As it exhausts its nuclear fuel, it will cast off its outer layers to form a planetary nebula that will surround its blazing hot core. Slowly the core will fade away over millennia as a cooling white dwarf. This is somewhat like the fate of most stars; however, very massive stars may end their lives far more spectacularly in a supernova explosion.