what is difference between subfolders vs subdomains in multisite

subfolders vs subdomains
A subfolder install means your sites will look like this:
Main site: http://example.com/
Sub Site #1: http://example.com/site1/
Sub Site #2: http://example.com/site2/
Sub Site #3: http://example.com/site3/
Sub Site #4: http://example.com/site4/
A subdomain install means that your sites will look like this:
Main site: http://example.com/
Sub Site #1: http://site1.example.com/
Sub Site #2: http://site2.example.com/
Sub Site #3: http://site3.example.com/
Sub Site #4: http://site4.example.com/

In addition, if you use a subfolder install, the post URLs on your main
site will have the slug /blog/ prefixed to them, causing them to look
like this:
http://example.com/blog/2012/03/what is fashion/ or
http://example.com/blog/2012/03/happy bidding !/ or
http://example.com/blog/2012/03/nice bidding/

Then it would be going a tough task to customize it
what is best subfolder or subdomain
that would not create any greater impact on it with seo perspective so do be emotional at all.
anyhow if you want to use subdomains , your server must allow wildcard with subdomains that normally happens.
This will allow you to create a new
subdomain site and have it automatically function

Can we install this feature on localhost
It would be impossible as that demands ip address configuration.
In addition, we cannot choose subdomains in the following cases: as the WordPress URL contains a path, not just a domain.