Rule 121.1 · Drawing a Card
A player draws a card by putting the top card of their library into their hand. This is done as a turn-based action during each player’s draw step. It may also be done as part of a cost or effect of a spell or ability.
Ask the judge Pro
The life counter has an AI judge that answers your play citing the exact rules. It is part of Gatewatch Pro; the rules, Oracle text and rulings stay free.