There are types of meringue that do not require baking. This type of meringue is known as a topping and is placed on the pie after it has baked.
This type of topping is cooked by the heat of the pie filling, preventing what is known as weeping in baking. Some types of meringue are baked on top of the pie. To prevent moisture from forming in-between the meringue and the filling the meringue should not be applied to a cold filling. To keep the meringue from shrinking away from the pie crust, it should be spread to the end of the crust.