Qlikview Server is where all the Qlikview applications are deployed, so that users can access those applications from Web Browser(Access Point). Qlikview Server has various components to handle these applications.
Qlikview Publisher is used to split the qlikview applications(as per user authorization), document reload, and distribution etc.
There is only one Qlikview software you need to install in the computer. Once after installation, enter server and publisher licenses in Qlikview Management console.
Most of the companies have Qlikview server license, and also go for Publisher license depending on their requirement.
Please go through the Server/Publisher Reference manual for more information.