I will explain the difference between managed VPS & unmanaged VPS in simple language. Managed VPS is the hosting type where you do not have to manage server related tasks such as managing & maintaining the server.
Managed VPS hosting
Managed VPS hosting varies from one provider to another, but if you’re not technically savvy, this “hands off” approach is your most viable option. It’s the ideal situation when you have little or no experience running or maintaining a server because the host typically takes care of software and system updates you request, and in some cases, does them pro-actively. Managed varies from one provider to another and is often referred to as a semi-managed service provider who helps you upgrade the core of the operating system (i.e. Linux kernel), but may not troubleshoot things that shared hosts would do.
Unmanaged VPS hosting
In unmanaged VPS hosting, the host is only responsible for the physical server and the availability of the server. Remember you need a vast amount of technical knowledge, and you should be familiar with the operating system and server software you choose to use. With the exception of the initial OS installation, the user is responsible for the maintenance, upgrades, and installation of software. Technical support is generally limited to hardware failure and outages, and you are responsible for backup services