For the following steps you need Confluence Administrator permissions.
Create Global Metadata
In order to create global metadata, you need to be a Confluence Administrator. Global metadata will be available in all Confluence spaces and helps maintain consistent metadata systemwide. To create global metadata, you first have to create at least one global metadata field and then add the field(s) to a global metadata set. Finally, you can assign your new set(s) to existing pages via bulk change.
Create a Global Metadata Field
As a Confluence administrator, go into the General Configuration and look for "Metadata Plugin" on the left sidebar. Click the entry "Metadata fields". You will now see the following overview:
Image 1: General Administration - Global Metadata Overview (click to enlarge)
Click "Add Metadata Field" on the right. This will lead you to the configuration screen for global metadata fields.
Image 2: General Administration - Add Global Metadata Field (click to enlarge)
Add Global Metadata Fields to a Global Metadata Set
The entry "Metadata sets" can also be found in the "Metadata Plugin" section on the left sidebar. On the page, click "Add metadata set" on the right to create a new set.
Image 4: General Administration - Add Global Metadata Set (click to enlarge)
Check section Add Metadata Fields to a Metadata Set in Manage Metadata in Spaces (v 2.0) to see how metadata fields will be added to metadata sets. These steps will also work for global metadata.
On the space and page level, you can add global metadata as described in the section Add Metadata to one or more Pages.