Hi Shardul Pasare,
Welcome to the MSDN forum.
According to your description, you can have a look at this:
https://www.visualstudio.com/products/compare-visual-studio-2015-products-vs that compare Visual Studio 2015 Offerings, and under ‘Development Platform Support’ we can find the ‘Office 365, Office, and SharePoint’ and ‘Cloud (Microsoft Azure)’ are supported
in VS community/professional/enterprise 2015 versions as below:

If we want to install the ‘Office 365, Office, and SharePoint’, we Requires installation of the
Microsoft Office Developer Tools for Visual Studio 2015
that are available at RTM. Download the installer and install it, then we can use the SharePoint in VS.
As far as I know, the ‘Cloud (Microsoft Azure)’ is shipped with VS, after you installed the VS 2015 version, you should find its related project templates under New Project windows.
About the difference, it looks like there is no specific document. You can look at the part ‘Subscriber Benefits’ in the above compare link. Since the professional and enterprise both
support them, you need to choose the appropriate one refer to your company condition and development requirement, like Enterprise organizations are defined as >250 PCs or > $1 Million US Dollars in annual revenue. Microsoft SharePoint Server is licensed
separately, about the SharePoint licensing: https://products.office.com/en-us/sharepoint/sharepoint-licensing-overview
Best regards,
Sara
We are trying to better understand customer views on social support experience, so your participation in this interview project would be greatly appreciated if you have time. Thanks for helping make community forums a great place. Click HERE to participate
the survey.