Actions used for workflows can be configured to allow users to add metadata to preset fields. This way, the metadata the user enters is applied to all the selected assets.

The system administrator may have configured actions allowing users to edit the metadata of the assets they're processing. Both the source asset and the destination asset can be updated. When a user runs such an action, a separate window opens where the user can edit the content of the fields defined in the action. 

Certain fields may have a taxonomy associated with them, in which case the taxonomy will pop up and allow the user to choose content from the taxonomy.

For more information about selecting assets and processing them with actions, see Processing assets using actions.