A pie can have a top and a bottom crust or just a bottom crust and is baked in a pie pan with sloping sides. A tart almost always has no cover, is baked in a pan with fluted or plain straight sides, often with a removable bottom, and is not as deep as a classic pie.
Most pie crusts, though not all, are fitted into the pan, the filling is added to the unbaked crust, and the pie is baked. Tart crusts are often prebaked partially or fully, known as baking blind, before the filling is added.