Regardless of the type of Visual Studio Solution you develop a regular web application or even a Windows application eventually you will need to "package" it for the purpose of deploying it to another server or client computer. Such packaging is varied and may be a Cabinet (
.CAB) file, a Microsoft Installer (
.MSI) file, or a
setup.exe (your classic setup wizard). The packaging format for SharePoint is a SharePoint Solution, having a file extension of
.WSP. A server administrator will be able to deploy your WSP file with a combination of PowerShell commands and/or Central Administration.
Some summary points about SharePoint Solution files: