On Microsoft Windows the preferences are stored in the HKEY_CURRENT_USER branch of the Windows registry. (LispWorks also offers a general Windows registry API, described in Accessing the Windows registry.)
On non-Windows the preferences are stored in subdirectories of the user's home directory.
To implement preferences for your Lispworks application, you will need to define a registry path using
(setf sys:product-registry-path)
.