We don’t use Phorest Salon Software but instead, use another software. Do we need to make sure that throughout the day, everyone logs in with their own password and signs out when finished?

Yes. Using PIN numbers will be mandatory after May 25th, 2018. GDPR requires you to provide a full, seamless audit trail on all data you collect and make sure that access is restricted to only the people who actually need it. PIN numbers make sure only the authorised staff member gets to see a specific type of information.