Proprietary Software is Microsoft Windows, Microsoft Office, Apple Mac OSX, Adobe Creative Suite
What is open source software
Software that has been placed in the public domain by the programmers. Users can see the source code and change or improve it. It is free to obtain and distribute.
Produced and owned by a person or company.
An example of open source software is.
Apple Mac OSX
Google Chrome
Microsoft Windows
Custom Written Software Off the self( Custom Written Software, Off the self ) is software specially commissioned / produced for a particular customer.