Creating Predefined Labels or Filters
Establishing chosen words for labeling and filtering content.
Although Confluence allows users to add and use labels in a free-form manner, in many cases it is better to create labels ahead of time so that content can be labeled from a predefined set of terms, thereby decreasing the chances of content being labeled incorrectly or inconsistently. These predefined labels, or filters, can also be used to narrow search results.
Adding a new filter to your site's taxonomy is simply a matter of placing it in a filter group.
Decide where the filter/predefined label belongs in your site's taxonomy
Navigate to the Targeted Search Filters page to view all existing filter groups. Is there already a filter group for this new filter? If not, you may need to create a new filter group.
Add the filter to the appropriate filter group
Click the gear icon 
that corresponds with your chosen filter group and select "Add Filter". You will be prompted to enter a human-friendly name for this filter (e.g., Human Resources) as well as the actual label string (e.g., human_resources).
Add a nested filter group
You can create filter groups within filter groups (called "subcategories"). Subcategories are always created under a filter. If you haven't done so, create a filter first, then click the gear icon next to this filter. Select "Add subcategory". You will be prompted to enter a human-friendly name and an optional prefix. The prefix is added to each of the filters within this subcategory.
Confluence's search engine breaks apart text strings that are separated by hyphens.
Labels such as part-time or world-class are automatically separated into part, time, world, and class, which can make search results from queries with hyphenated terms less relevant. For this reason, we advise against using hyphens in labels and recommend using underscores (_) instead (e.g., part_time, world_class).
The corresponding human-friendly name for any filter can include hyphens, spaces, and uppercase letters (e.g., Part-Time, World Class).
