hi,

see you need to enroll for the particular course like bachelors or masters degree in university of mumbai, must complete the course in stipulated time, clearing the all examinations and other academic curriculum. however for alumni students the university of madras is going to open an online platform in which students who have already passed any degree course from university of madras may download the certificates. however the process is still going on.

however you may apply for duplicate certificates by submitting the application form ,

follow the below link to know in details,

https://www.unom.ac.in/webportal/uploads/downloads/duplicate-degree-application_20160922091831_68059.pdf