Suppose I have to create a graph with 15 nodes and certain nodes. Instead of feeding the nodes via coding, can the draw the nodes and links using mouse on a figure? Is there any way to do this interactively?
No.
Sorry.  In principle it could be possible to create a GUI which interfaces with networkx (and maybe some people have), but it's not built directly into networkx.
Python : Is there a way to interactively draw a graph in NetworkX?