What’s the safest way for contractors to receive company alerts on personal phones?

If they truly need access to your Microsoft 365 mail or apps from a personal device, use mobile application management and app protection policies. Controls can require a PIN, block copying and screenshots, restrict data sharing, and remove organizational data when access is revoked. Check licensing and guest-account requirements first—these policies may require additional licenses, and they still leave you responsible for managing those external identities.

A dedicated alerting service may be a better fit than email. Contractors could subscribe to narrowly scoped notifications through an authenticated app or notification endpoint, with separate channels, expiration dates, and audit logs. Just make sure the service supports access revocation and does not expose confidential alert details.

For anything more sensitive than a basic notification, provide a company-managed phone or another dedicated device. Asking someone to read company information on a personal device without supplying an approved endpoint creates a policy exception and makes incident response and offboarding much harder.

The simplest option is to send only the necessary alerts to the contractor’s existing company email address. Their employer can handle mobile access, security, and offboarding, while you avoid creating internal mailboxes or granting unnecessary tenant access. Use a distribution group or alerting system that supports approved external recipients, and make sure the messages do not contain sensitive information.