121.2 Cards may only be drawn one at a time. If a player is instructed to draw multiple cards, that player performs that many individual card draws.
121.2a
An instruction to draw multiple cards can be modified by replacement effects that refer to the number of cards drawn. This modification occurs before considering any of the individual card draws. See rule 616.1g.
(refs: 616.1g)
121.2b
Some effects say that a player can’t draw more than one card each turn. Such an effect applies to individual card draws. Instructions to draw multiple cards may still be partially carried out. However, if an effect offers the player a choice to draw multiple cards, the affected player can’t choose to do so. Similarly, the player can’t pay a cost that includes drawing multiple cards.
121.2c
If more than one player is instructed to draw cards, the active player performs all of their draws first, then each other player in turn order does the same.
121.2d
If more than one player is instructed to draw cards in a game that’s using the shared team turns option (such as a Two-Headed Giant game), first each player on the active team, in whatever order that team likes, performs their draws, then each player on each nonactive team in turn order does the same.