The Confluence-administrators can set the global watermark. Click "Manage apps" – "WATERMARK FOR CONFLUENCE" – "Global Watermark Settings" to enter the Global Watermark Settings page.
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If "Force Watermark in all spaces to use follow with the global watermark settings" is enabled, the watermarks for all spaces will follow the are determined by global watermark settings; if it is disabled, the space administrators can customize space watermark separately. For more details, please refer to 2.3 Space watermark settings