Hey!

In most of the colleges, there is no system of offline application for postgraduate admissions nowadays. The whole application process is completely online, and all the required documents are supposed to be uploaded online in the application form itself.

If you are talking about some specific university, please specify. Usually, no documents are supposed to be mailed to the institute. Once you secure admission there, you will be asked to visit the campus and submit original+photocopies of documents there itself.

Hope it helps!