ID3D11DeviceContext::Draw method (d3d11.h)
Draw non-indexed, non-instanced primitives.
void Draw( [in] UINT VertexCount, [in] UINT StartVertexLocation );
Number of vertices to draw.
Index of the first vertex, which is usually an offset in a vertex buffer.
Draw submits work to the rendering pipeline.
The vertex data for a draw call normally comes from a vertex buffer that is bound to the pipeline.
Even without any vertex buffer bound to the pipeline, you can generate your own vertex data in your vertex shader by using the SV_VertexID system-value semantic to determine the current vertex that the runtime is processing.