Expertise in design and implementation of complex SharePoint solutions
SharePoint is a web-based, collaborative platform that integrates with Microsoft Office. Launched in 2001, SharePoint is primarily sold as a document management and storage system, but the product is highly configurable and usage varies substantially between organizations
Provider Hosted App is one where the app is hosted outside of SharePoint. For Example, a server hosting IIS can host the app contents in a site. This is referred to as a remote web. This is more of a hybrid in that it can run a mix of both client and server side code. Feel free to read up here for more details.