A dashboard is saved as an item within ArcGIS Online and by default is only accessible to you. You can choose to share the dashboard with your organisation, groups you belong to, and everyone (public), depending on your sharing privileges and the security settings of your organisation.
To share the dashboard, you will need to access the item in ArcGIS Online.
1. Go to the Dashboard Builder Home screen and browse to the dashboard.
2. Click on the icon to go to the item in ArcGIS Online.
3. In ArcGIS Online, click Share and select the group you wish to share the dashboard with.
4. Click OK.
The selected group(s) will now be able to view the dashboard via the dashboard URL, as specified on the ArcGIS Online item page.