how can i create a basic shape and put it in tools (Basic Shapes) to use it
in any time after that
I don't think you can add shapes to the basic shapes but you can
create your own stencils and add shapes to them.
If you open a blank drawing and create your shape on that. Then create
a new stencil ( menu File | Shapes | New Stencil ) and drag your new
shape to this stencil. Save the stencil of course.
