Hi Pramod
Competencies can be assigned to users by creating a learning plan and adding a competency.
See http://help.totaralms.com/Managing_Competencies.htm for how to set up competencies
See http://help.totaralms.com/learner/Create_editing_learning_plans.htm for how to assign the competencies.
Is this what you were wanting or were you wanting a way of automatically assigning these to a user when enrolling .
See http://help.totaralms.com/Learning_Plan_Templates_v1_1.htm for the learning plan automatic assignment options.
Craig