ShiftCare send automatic invite to staff when you generate staff's profile (add staff). If you don't wish to send invite until you are fully ready then you can do so by not adding staff's email.
Because adding staff email is mandatory, so you can replace email say firstname.lastname@example.org.
Once you are ready, you can start sending invite by adding their actual email's. But make sure you click on Resend invite after changing their emails.