Form is the 3D representation while shape is 2D, we build the forms out of shapes that we overlay to create the illusion of depth. By applying proper use of color mixing we can create values for our forms.
Both form and shape can be used in design through an illustration that uses either or both to create a reality in the work or we could make a graphic design where shape language, or the use of line types to convey personality and mood, to create appealing designs. By working in both shape and form you have an understanding of balance in your work, how to break down complex real life forms, and how to tell a story through the study of them.