You can create filters explicitly, but filters can also be created implicitly as a result of other actions such as drilling on a visualization.
To add a filter to a project:
Note:
When you work with visualizations that are part of master-detail relationships, your data selections in the master visualization apply a filter to all the other visualizations on the canvas. For more information on master-detail relationships and synchronizing visualizations, see Specifying How Visualizations Interact with One Another.