SharePoint is a technology that organizations and business units of all sizes use to improve team productivity and to increase the efficiency of business processes.
SharePoint capabilities are available in SharePoint Server 2016 and SharePoint Online.

SharePoint Server 2016 gives you a powerful toolset for organizing content, managing documents, sharing knowledge, providing robust collaboration environments, and finding information and people. You and your colleagues can use the social functionality in SharePoint Server 2016 to build communities, share thoughts and ideas, and discover resources and knowledge in your organization.

SharePoint Server 2016 helps teams stay connected and productive by providing an infrastructure and capabilities that allow easy access to people, documents, and information that they need. By using SharePoint 2016, teams can create websites to share information and foster collaboration with other users. You can access content stored within a SharePoint site from a web browser and through client programs and apps, such as Office, running on multiple devices.

In addition to SharePoint Server 2016, which resides on one or more servers in your organization (that is, on-premises), SharePoint capabilities are available as a webbased service called SharePoint Online that is hosted outside your organization in the cloud. “In the cloud” means that the IT infrastructure resides off your organization’s property (that is, off-premises), and that the infrastructure is maintained by a third party. SharePoint Online is a cloud service that you can use to access information and interact with your team from nearly anywhere, on many types of devices.

SharePoint Online is a subscription-based service. Instead of installing SharePoint Server 2016 software in your organization, you can buy a subscription plan to use
this software as a service. SharePoint Online is a part of Microsoft Office 365, which also includes Microsoft Exchange Online for web-hosted mail service and Skype for Business for web-based conferencing. There are a number of subscription plans available that provide different sets of features and capabilities, from basic to enterprise level, for a monthly fee. The SharePoint Online service is available as a part of multiple Office 365 subscription plans, or as a standalone subscription plan.

For more information about Office 365 SharePoint and available plans and pricing, go to https://products.office.com/en-us/sharepoint/compare-sharepoint-plans