Hi Mohamed, there is a link when you click on Certifications within the Academy: https://academy.mendix.com/link/classrooms/3/intermediate/Course
There is no apparent online link on academy.mendixcloud.com to sign up for the exam. This is just for the course https://academy.mendix.com/link/certifications. Drop them a line at academy@mendix.com and they will let you know how to sign up.