A defender plays a card by placing it face up on the table in front of him. If a defender places a card in such a position that the other defender can see the front of the card, it counts as played.
Declarer plays a card in a similar manner and any card placed face up, on or near the surface of the table, by declarer counts as played.
Declarer plays dummy’s cards by either naming them (the correct procedure in duplicate bridge) or physically handling them (in rubber bridge).