Data residency is where your data is physically stored and processed, and which jurisdictions’ laws consequently apply to it. For European organisations the usual requirement is EU or UK hosting; regulated industries and governments often go further.
Workplace platforms hold personal data, including names, schedules, visitor records and sometimes vehicle registrations, so residency belongs on the procurement checklist alongside GDPR compliance and security certifications. Ask where data lives, who can access it and under what agreements it transfers.