Short answers, pulled from the story.
Gary Gygax released the first edition of Dungeons and Dragons in 1974, introducing the elf as a playable race for the very first time. Dave Arneson added the aquatic elf to the Blackmoor supplement just one year later in 1975.
Elves become physically mature at the age of twenty-five yet do not reach emotional maturity until around one hundred twenty-five years old. They live for more than half a millennium while remaining physically youthful throughout their long lives.
These early elves could multiclass but faced strict level caps of four levels in fighter and eight in magic-user. These restrictions remained in place until the third edition of the game arrived in 2000.
The Forgotten Realms setting features surface elves called Tel-Quessir which means The People in the elven language. These elves include green elves, lythari, avariel, dark elves, sun elves, moon elves, and wood elves.
Wizards of the Coast announced in December 2022 that the word race would no longer refer to biological traits but instead use species. This change went into effect with the December One D&D playtest release.