You can maintain a number of KeyStores. For example, you might have a personal KeyStore which you alone use. Your company could also maintain a central KeyStore for contacts which are common to the whole company. This could be kept on a shared drive.
The KeyStore is stored as a file. You can change the location of this file through the Option menu.
PrivateFile Keystore
You can use the PrivateFileKeyStore to store the keys that you regularly use. This is for use with PrivateFile Desktop. For example, if you often send encrypted attachments to the same recipient, you can store their keys in the KeyStore. The KeyStore is itself protected using the KeyStore passphrase. Make sure to remember this passphrase or you will not be able to access the keys stored here.
You can use the Generate Key option to create a random key.