With a dedicated server, you can install any operating system. Cloud VPS offers a limited selection (at Liquid Web, it’s CentOS 6, CentOS 7, Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, Debian 8, Windows Server 2012 R2 Standard, and Windows Server 2016 Standard Edition.) Otherwise, both options give you full root access with control over the OS and all the software in the environment.
The web hosting company will also provide regular web server software, installed programming language extensions, & firewall upgrades. Managed VPS plans running Windows normally include the use of Plesk for administration of domains and web server settings, while VPS plans running Ubuntu, Debian, Slackware, etc. can be administered using Webmin or Virtualmin under a free open source license.

As you can see, a VPS can be the perfect middle ground for many – enough flexibility and resources for those who need more access or control than on a shared server but without the cost of a dedicated server. If you need root access, you can’t get that on a shared server, but you can get it on a VPS. If your site experiences unpredictable swings memory usage, and your host provides it, then the presence of burstable memory will be attractive. And, if you’re a fan of customization, then the fact that you can customize server-level software such as PHP, MySQL, and Apache will perk your interest.  In short, choosing a VPS will allow you to have many of the same characteristics of a dedicated server but in a more affordable and manageable package.
Nice read Rahul ! While you compare all hosting types, I would like to point out one important thing related to shared hosting. Undoubtedly, VPS hosting has become the most popular hosting type in short span, but shared hosting has its own benefits. First and most important one is – Shared Hosting is by Default Fully Managed, that means you don’t have to worry about security of your website, server updates, software update, spamming from your mailboxes, etc.
Think of a shared server as a large apartment complex, and all of the individual apartments are rented by other website owners. All of you need a place to live — just like your website’s files — but going out to buy a huge family home would be too expensive for your needs. Sharing common areas and utilities in an apartment block helps keep costs down. And the same is true for shared hosting.
In answering this question, maybe it’s better to examine how VPS hosting fits in to the overall offerings of most hosting companies. Shared hosting is just that – your site is hosted on a machine with a bunch of other sites, and each of you share the same resources, including RAM, disk space, and CPU.  Your site uses what it needs if it’s available, and if it’s not – well, that’s the limitation of shared hosting. Likewise, a dedicated server is also self-explanatory –  your site is the only one hosted on server, and you have all the aforementioned resources available at your beck and call. Dedicated hosting is therefore  for those large sites with big databases and lots of traffic, whereas the limitations of shared hosting’s usually prevent it from housing that kind of site. Dedicated servers are also relatively expensive, while one can get a shared hosting plan for under $10 per month.