Components can have an unlimited number of values (attributes), allowing you to enhance the information stored with each Component by adding fields such as Manufacturer, Manufacturers Part Number, Bin Number, Distributor, Tolerance, MTBF Value etc.
When editing the Component in the Library Manager, choose the Edit menu and Values option to add Values and their own value string to the Component. Remember to save the Component to the Library once you've finished.  Alternatively, in the Library Manager on the Components tab, click on the Values button in the centre column to open a dialogue to globally edit values for the library contents. Press <F1> for help with this.
Adding a new value to a component will add the same value to all packages.  If different values are required (such as manufacturers part number for different footprints) it's a little more complex.  You need to edit the component, in turn make each package current on the package tab, then adjust the value on the Values tab before saving back to the library.
You must also use the Update Component option from the context menu for a selected Component in the design to reload it once any new values have been added to it. You must do this for both the Schematic and PCB designs.
If a new Component is being added to the design, it will take whatever Values have been added in the Library editor.  These can be modified locally, but cannot be deleted.
To view Values for a Component select it in the design and use Properties from the context menu.  Alternatively, Component Values on the Settings menu will display all values in the design.
You can add extra Component Values fields into a Parts List or BOM by opening the Parts list under Reports or the BOM under BOM Composer, both on the Output menu.  Once open, press <F1> for detailed help on adding extra value fields.