Short answer: Not for everything. Preventive care is covered free even before you meet your deductible, and many plans also pay for certain services, like a primary care visit or generic drugs, for just a copay before the deductible. For most other care, you pay the full negotiated cost until you reach the deductible, after which you usually owe only a copay or coinsurance.
A deductible is the amount you pay for covered services before your plan starts paying, but it does not apply to everything. All Marketplace health plans pay the full cost of certain preventive benefits even before you meet your deductible, so recommended screenings, vaccines, and similar services stay free regardless of where you are with your deductible.
Beyond preventive care, many plans cover some everyday services with a copay before you meet the deductible; check your plan to see which ones. Some plans also keep separate deductibles for certain services, like prescription drugs. The federal preventive rule is firm: for in-network recommended services, a plan must provide coverage for and must not impose any cost-sharing requirements. And no matter what, your total spending each year is capped by your out-of-pocket maximum.