How did the rings in the Lord of the Rings come to be?

Answer 1

The One Ring was created by the Dark Lord Sauron during the Second Age in order to gain dominion over the free peoples of Middle-earth.The Rings of Power in J. R. R. Tolkien's Middle-earth legendarium are magical rings created by Sauron or by the Elves of Eregion under Sauron's tutelage.

However, when Sauron forged the One Ring, the Elves he had tutored sensed its creation and hid the other rings from him. He came to their crafting halls, slew the chief craftsman (who also helped make the Doors of Moria and who inscribed letters onto Narsil), and stole sixteen of the other Rings - the Elves had been able to hide three of them.

Sauron, still trying to appear gracious to the other Races, gave seven to the Dwarf-lords. Their Rings were the foundations of their hoards, apparently able to draw wealth to the bearer.

Nine of the Rings, Sauron gave to Men, who took them, for the Rings made them mightier and more powerful; with the Rings, they would not die. However, as they would learn later, neither would they live. These Men became the Nazgul, Ringwraiths.

The Three were hidden from Sauron - his hand never had touched them in their making, nor had he overseen these Rings' creation (they had been made by the chief craftsman).