hi @Kailash_Kumar
If your are 100% sure about your running robot is Unattended , so that robot can be pass its own windows credential itself (you have to provide exact and correct domain/user name and password in the relevant unattended robot ) if you using that it can be log and do the task.
But as you say that “Is there an option to run it when the screen is locked” no its cannot .
to run the job either it should be pass the credential and run the robot or should turn on machine screen(without lock)