Metadata fields can be defined as Text, Date, Select (Picklist), or Multi-select. Individual fields can also be set as required. Individual fields can also be defined to display in the Current card view in the documents pane.
Here are the steps to add metadata
Click on Documents
Navigate to the document you wish to add Metadata
In the document detail pane click on the Metadata button
Choose the version from the drop down menu
Choose a document type from the drop down menu
Enter the data into the fields provided and click “Save Metadata”
The metadata is now part of that version