You may add one or several filters to data on a report. For example, on "Application usage" report, you may want to filter on the application name. Let's filter on the applications whose name begin with "Microsoft" :
First, select filters of the report :
Then, a window is open with the list of current filters. You will always have a filter with server names or website names, it is mandatory, please ignore it (you can remove it, but then it will be added again automatically).
Click the "+" button to add a filter.
Choose the field on which you want to apply the filter (in this case, the process name), and then the filter operator and the value :
Then click on "OK", save the custom report, and access it to see the results filtered :