Doors for sheds can be purchased at stores such as Sheds Unlimited or The Shed Shop either through their physical stores or, in some cases, via the phone. There are some types of doors available at home improvement stores such as Home Depot or Lowe's, but the selection is very limited and only works with cloth-type structures.
The sites give you several options of materials to choose from along with various sizes. The standard sizes are 3-foot-wide doors or 6-foot-double doors. The selection of door types offered by these stores makes it easier for consumers to find a door that matches not only the look of the customer's shed, but helps make sure it meets any building regulations required for their area.