In result lists, custom properties for each found document are listed together with its other information (such as title, date, description, etc.). To the user, custom properties are indistinguishable from standard properties, though you might choose to format them slightly differently.
One place where custom result properties are often used is on a result-details page, which shows extra information about a single result selected from a result list. Here, the user will be able to see many more properties than are normally included in the list view.
All custom properties used in search results must be mapped to SharePoint managed properties, which themselves exist as database columns for each document.
Figure: Example of a detailed result page that shows several custom result properties about a selected document