Does drawing a card during your draw step count as one draw or can effects make it multiple draws?

By default, the mandatory draw at the start of your draw step is a single card draw — you draw exactly one card. This is governed by CR 504.1, which states that the active player draws a card during the draw step. That is one draw event, full stop.

However, replacement effects can modify this single draw. The most famous example is Howling Mine-style effects or enchantments like Teferi's Ageless Insight, which replace 'draw a card' with 'draw two cards instead.' Under CR 614.1a, replacement effects modify how an event occurs. So your one draw-step draw can become two or more draws due to such effects.

It's important to understand that each individual card drawn in a sequence is still its own separate draw event for purposes of triggers. For example, if an effect says 'whenever you draw a card, do X,' and your draw step draw is replaced to draw two cards, that triggered ability will trigger twice — once for each card drawn (CR 603.2).

Concrete example: You have Teferi's Ageless Insight on the battlefield. During your draw step, you would draw one card. Teferi's Ageless Insight replaces that draw with 'draw two cards instead.' You now draw two cards, and any 'whenever you draw a card' triggers fire twice.

So the answer depends on whether replacement effects are in play. Without them, it's always exactly one draw. With them, it can become multiple draws, and each individual draw in that sequence counts as its own draw event for trigger purposes (CR 504.1, 614.1a, 603.2).