Doors are settlement object in Fallout 4 and its add-on Wasteland Workshop.
Doors are either wooden or steel and come in different colors. They can be snapped into any doorway structure in a settlement. The broken and chain doors can be shot through.
Doors are located under Structures → Doors in the workshop.
Seventeen doors can be crafted in the workshop. An additional four are added with the Wasteland Workshop add-on.