To whom does the elder address 2 John?

Answer: The chosen lady and her children

2 John opens, "The elder, To the chosen lady and her children, whom I love in the truth" (KJV: the elect lady).

“The elder, To the chosen lady and her children, whom I love in the truth—and not I alone, but also all who know the truth—”— 2 John 1:1 (BSB)