DecoratorField is an Orchard module.
It adds a new Field DecoratorField to Orchard.
This field usage is mainly for decorating Custom Content Types edited in Custom Forms.
The usual way to improve a Custom Form design is by css, adding DecoratorFields to your Custom Content will provide more possibilities because DecoratorField introduces any display tag in your html.
This field has no input value, only settings you define when adding a DecoratorField to your Custom Type.