Report parameters allow the user to supply information to the report being executed. 

Several types of report parameters are available, all of which include a display name and parameter name.

To use the report parameter within the report simply reference the parameter name within the SQL statement, for example

WHERE ([ItemCore].[Name] LIKE @ServerName)

If the SQL statement of the report contains a parameter that has not been defined as a report parameter an error similar to the following will be displayed to the user