Applying workflows to digital assets is the same as for website pages. For a complete guide on how to create and use workflows in AEM, see Starting Workflows.
Use workflows in digital assets to activate the asset or create watermarks. Many of the workflows for assets are automatically turned on. For example, the workflow that automatically creates a rendition after an image is edited is automatically turned on.
For details of applying a workflow to an AEM asset, see Starting a Workflow on an Asset.
The procedure to apply a workflow to multiple folders is similar to the procedure to apply a workflow to multiple assets. Select the folders in the Assets console, and perform steps 2-7 of the procedure Applying a workflow to multiple assets.
For details of applying a workflow to a collection, see Running a workflow on a collection.