Mohammed - this is an often-asked question on RG. The market leader is most likely 'Turnitin' - but it requires subscription. Also - these software systems are basically 'cross-checkers' against direct match. They are, therefore, just text-matching tools.They don't 'prove' plagiarism; that depends far more on the policy processes of individual universities and the 'tenacity' of lecturers to follow-up.