To add voice notes to statuses you only have to use the microphone that will appear in the same composer that is used to write and publish text in the states. As with the rest of the content, this type of publication will last 24 hours.
The voice notes that are shared in the states They can only be heard by the contacts that the user has chosen. By default, the entire agenda of an account is included, but each person can make restrictions in the WhatsApp configuration.