A Tag Report generates a summary of Tags and associated modules.  To run a Tag Report, start by clicking on the 'Tag Report' link under the 'Content ' heading in the 'Reports' menu.  You can filter by Positon, Tag, Tag Type/Category, and module.  Once you have set any filters, click 'Export Report Data to Excel'.

This will generate a .xlsx file with your report data.  Below is sample report output.