All sheds require a foundation. Most models give you the option of building your own or using a pre-made kit. There isn't any structural advantage to using a kit created by the manufacturer, but it is easier and will definitely save you time.
Not all storage buildings need to be anchored, but many do and it's usually a good idea if you live in an area prone to high winds. As with foundations, most manufacturers will give you the option of using one of their kits or your own materials.
If you live in an area that routinely gets a lot of snow you may have to get one of these kits in order to meet local building codes. They strengthen your shed's roof and increase the amount of snow it can safely support.
Shelving and Racks
When it comes to adding shelving to your storage shed you've got quite a lot of options. There are shelves that can be mounted directly to the wall of your building as well as freestanding racks. You'll even find hooks designed for storing tools and gardening equipment. The racks can obviously be used wherever you need them, but many of the wall-mounted shelving units can only be used with specific models or brands so make sure that you check the manual before buying.