There are often two varieties of server hosting compared: self-managed, and fully managed service.

Managed hosting usually includes benefits like:

• Guaranteed resolution of software issues, which may not be related directly to a server or the provider’s service.
• Installation of custom/third-party software, upon request.
• Advanced optimization and management of the server’s operating system and software packages.
• Optimization and monitoring of the server’s security, including firewalls.
• Monitoring of the server’s health and activity.
• Proactive maintenance based on server status and health reports.

In contrast, self-managed hosting may include all of the above, but on a on-request basis only, or as required by a customer’s chosen support level. Managed hosting is meant to be comprehensive, providing “360-degree” oversight and maintenance of servers.

[Via https://www.redarray.net/portal/knowledgebase/30/What-is-managed-server-hosting.html]