Some suppliers price a list you send. Others do their own takeoff from the plans and quote a full package.
A lumber yard may quote a framing package from the drawings. A drywall supplier may quote board, studs and mud from your quantities.
If the supplier did the takeoff, check its quantities against yours. You own the shortfall if its count is low.
Confirm the units on every line. Confirm delivery terms and how long the price is good. Material prices can move between bid day and the order.