Publishing/hosting is a service that makes your application publicly available. Applications can be stored on servers provided by your hosting provider. In this section, we will use TFS (now VSTS): refer to https://www.visualstudio.com/tfs/.
You need to migrate your existing project if it is hosted on TFS. Refer to the link for more details: https://www.visualstudio.com/team-services/migrate-tfs-vsts/.