how many types of ways are there to enter into IIT & graduate from IIT, from all fields of Programs offered by IIT’s

e.g; 1. after 12^th we can enter into b.tech or m.tech by writing JEE, 2. after graduate degree’s from various universities we can enter through JAM entrance

@ venkat 
that will vary from diffrent iit depending upon their course structure and catagory ., 

one is after clearing your jee advanced exam , in btech catagory , anathor is for msc candidate through JAM , 
anathor is through GATE for mtech in iit , 
and also there aree more research programme in iit , in which u can enter through GATE 
kindly check it in the respective iit website