How I can insert label on each line in plot3

I draw some lines in 3d space with plot3.

I want to insert label (for example numer, i.e. 1,2, 3, ...) on each line after drawing each line in 3d space. How I can do it?

Answer 1

[madhan ravi]

see label and legend

xlabel('x')
legend{'1'}

[Alireza Entezami]

Thanks for helping me. But I have another problem.

As you can see in attached file, I want to know that how i can write the number of each line on each line in figure as an annotation. I want to insert the number of each line on it during the drawing in plot3 comment.