This information is found in the FAQ.:
"A draw can be claimed without any interaction from your opponent under a number of conditions. These are as follows:
No piece capture or pawn movement has occurred for over 50 consecutive moves (100 half moves). Therefore the game has not progressed and a draw may be claimed by either player during their next move.
Insufficient material remains on the board to finish the game. If only two kings remain then either player may claim a draw during their next move.
Third repetition of a position. If any identical position appears three times during a game, then the game can be claimed as a draw. Please note that each repetition must be identical with regards to en passant and castling availability. A draw can only be claimed along with a move that contributes to a repetition. Claiming after the repetition has occurred is not possible, unless the same position can be repeated again on a future move."
<It is my understanding that none of these are 'automatic'. If a player thinks any of the above conditions exist, they must CLAIM the draw. Otherwise, the game will just go on.>
What is not mentioned in the FAQ is that if one player offers a draw at any time along with making a move, the other player can accept the draw offer, and the game will end at that time as a draw. There are no other conditions required. One person offers, and the other accepts. So if both players agree to the draw, the game ends. If the other player does not want to accept the draw, they just make their next move and the offer is automatically declined and the game continues.