https://plus.google.com/+Mashable/posts Example ... I want to change my https://plus.google.com/u/0/b/117639066038692399181/117639066038692399181/posts to shorter URL like above ? How can I do it?
So-called "vanity URLs" aren't available to everyone yet. It's being rolled out to verified members and pages, but so far seems to be limited to well-known names/products/sites. Once it's available to everyone, you should be able to get it as long as you have verified your Google+ account.
Google+ vanity URLs are only available to a limited number of verified profiles and pages. Check this official post.
There are so many "pride URLs" aren't obtainable to everyone yet. It's being turn over out to established affiliate and piece of paper, but so far seems to be inadequate to well-known names/products/sites. Once it's available to everyone, you should be able to get it as long as you have verified your Google+ account.