NoteCaddy note and color definitions are just xml files. This means they can be shared among friends easily. Also, keep in mind that the definition digest is also available for the procurement of many free definitions. It can be accessed via tools->definition digest.
Once you have an xml file, you need to import it into NoteCaddy. The easy way is shown in the below screen shot
If you have multiple definitions in the same folder, you can select them all at once.
Color definitions are always found in a file named colordefinitions.xml. It is a single file for all definitions. If you import a colordefinitions.xml file, it will add the definitions to the ones you already have. If there is an overlap then your existing definition(s) will be overwritten.
Importing definitions will create
Pending Tasks that will need to be run to ensure that your data is accurate.
In the event that you experience any difficulties importing, you can still copy the xml files into the NoteCaddy definitions folder manually. This should be done while NoteCaddy is closed. If you're running NoteCaddy as an HM-App then HM2 should be closed.
For NoteCaddy standalone, copy the files to c:\program files (x86)\notecaddy 2\definitions
For the HM-App, copy the files to C:\Users\{YourWindowsLogin}\AppData\Roaming\HoldemManager\NoteCaddyDefinitions
Important: if you import a definition by copying the xml file to the notecaddy definitions folder directly, no pending task will be created and you will need to reset/recreate notes