If elements we have on earth were developed from stars, how did they reach earth?

In the 9 Billion odd years that the universe existed before the Earth formed there were plenty of stars that went supernova and blew the elements into space. When the cloud of gasses and debris that would become the sun and planets of our solar system formed these elements were present and were collected inside as the earth as it formed.

What the first answerer said is 100% correct. The elements were developed in stars and then those stars blew up in a supernova which than released a lot of dust, a very lot of dust and nebulae into the universe and from that nebulae and dust where those materials were present already, formed the planets like Earth and so on. The nebulae coalesce into spheres which then harden over a very long period of time forming the Earth and the other planets with the elements which have developed in stars present in the dust so when the Earth formed and hardened, the elements then became present very deep under the Earth. So if you have a gold ring, make sure that you appreciate it because that ring was once inside a real burning star. The guy above me says that all the matter in the universe came from our star, I find this hard to believe because all the matter in the universe was created in the big bang from which formed the stars in the universe. So I think that he stands corrected. How can so much of planets and matter in the vast universe come from only one single star? The answer is that it doesn't.

From what I understand, when the energy of a star condenses it will explode. According to physicists, the big bang theory is one theory that mathematically works. Just like a bottle will eventually explode in heat or a can of soda will expand in a freezer. The energy of an explosion pushes or shoots the elements in all different directions. In space the only way elements can really travel is through acceleration, the only way acceleration is possible is from the energy of an explosion. Gravity is another form of energy, but this energy fluctuates depending on where the stars lie within other gravitational fields and the elements that "fall where they lie". All planets surrounding the sun are made with the same elements but to different degrees. Regardless of that fact, the elements that make up earth are just the right amount controlled by the energy or gravitional field of the sun and the elements of our earths core. Hope this makes sense.

Massive stars generate elements in their cores and (especially) during supernova events. Massive stars might only live for a few tens of millions of years. A lot of that material gets ejected back into the interstellar medium where it cools, mixes with other gas, and eventually becomes incorporated into star-forming clouds.

Stars in the Milky Way were doing this for billions of years before the formation of the Solar System.

all the planets and matter in our solar system come from our star.