Organizations use Microsoft SharePoint to create internal company websites, known as ‘intranets’.
SharePoint empowers teamwork with dynamic and productive team sites for every project team, department, and division.
Share files, data, news, and resources. Customize your site to streamline your team’s work. Collaborate effortlessly and securely with team members inside and outside your organization, across PCs, Macs, and mobile devices.
As they explain in the documentation Apps are small, easy-to-use web applications that add functionality to SharePoint sites. They offer unlimited possibilities for customizing your sites in ways that are specific to your organization.
For example, you can add apps that perform general tasks such as time and expense tracking, or apps that make it easy for customers to contact you, or productivity apps that enable you to establish data connections and develop reports for your stakeholders.
There are two basic kinds of SharePoint Add-ins: SharePoint-hosted and provider-hosted. To make the best decision about the right kind to develop for your scenario, start by learning what both types of SharePoint Add-ins have in common.