I have 2 options for you.
1) In the online reports, you can enter a value in the column filters. These appear at the top of the online report columns. You can do this for multiple columns if you'd like. As you enter the value in the column filter, you'll see the content of the report change to meet your filter criteria.
2) If you export the online report into an Excel file, you can add Excel filters to the report and then use the standard Excel filter options to customize the view.
Based on how sophisticated you want to create and apply filters, you can use option #1 or option #2.