Generally no. If you are using Whova's registration you will need your attendees to purchase or sign up using the registration. If an attendee pays by cash or check, you are able to register for them by adding them manually to the dashboard. See Attendees tab > Add Attendees.
If you need to upload a large list and are using Whova's registration, please contact your customer support specialist or email us at firstname.lastname@example.org.