Edx is a mooc ( massive open online couse) website which has many variety of online courses which are free for everyone .There are numbers of categories such as-technology , economics, agriculture, medical, drawing, aerodynamics, mechanical, data analysis, dashboard design you have to just visit https://edx.com and sign up for this website and you are free to register any course, the materials of any course is very precise and accurate with full details and there is also instructor which will guide through out the course with out any fees .The fees is required in some course if anyone wants pursue certificate and if somenone wants only completion cerficate then they will get once you pass the eligibilty criteria in the test.
