Promotion

A pawn that reaches the farthest rank must become a queen, rook, bishop, or knight of the same colour.

The choice is not limited by previously captured pieces, and the new piece takes effect immediately. Choosing a piece other than a queen is called underpromotion.

A pawn must promote on the last rank

A pawn that reaches the farthest rank is replaced on that same move by a queen, rook, bishop, or knight of its colour. It cannot remain a pawn, and promotion does not depend on whether that piece was captured earlier.

Move the pawn from e7 to e8 to promote it to a queen.

The pawn on e7 must become a new piece when it reaches e8.

Promotion does not always mean a queen

Choosing a rook, bishop, or knight is called underpromotion. A knight promotion may give a check a queen cannot give, while choosing a less powerful piece can sometimes avoid stalemate.

e8=Q: The e-pawn promotes to a queen.
e8=N+: The e-pawn promotes to a knight and gives check.

The new piece acts immediately

The promoted piece exists as soon as the move is completed. Its attacks can give check or checkmate on the promotion move itself.