Mohamed,

You'll need a graphics library.FORTRAN, by itself, knows nothing about graphics.

Which version are you running, and in what environment?

A lot of people use R for graphics.  What sort of data and FORTRAN program are you working with?  You may find that there are better tools with more dedicated functions for your area.

I found a similar question with an answer in the following link:

https://www.researchgate.net/post/How_do_I_obtain_a_plot_of_my_Fortran_results

Also, you may benefit from the links below:

https://www.youtube.com/watch?v=LqVkZbcoceY

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=0ahUKEwiP4Lig9d3JAhWG93IKHQQpC8gQFghDMAU&url=http%3A%2F%2Fwww.ill.eu%2Fnc%2Fpress-and-news%2Fpast-events%2F2009%2Fcsdc%2Fcourses%2F%3Fcid%3D20263%26did%3D45101%26sechash%3D3c407087&usg=AFQjCNHNe_YA0TAooyn5OITp1giheCrMjA&sig2=I7L8fmyi1WwjrzG-jOdjXQ&bvm=bv.110151844,d.bGQ

All the best.

thank u all for your answers