, the hub for teamwork in Office 365, rolled out a new ability to facilitate collaboration. Previously, anyone with an Azure Active Directory (Azure AD) account could be added as a guest, from now on Microsoft Teams anyone with an email address can be added to a team in Microsoft Teams. This means that anyone with a business or consumer email account, such as Outlook.com, Gmail.com or others, can participate as a guest in Teams with full access to team chats, meetings and files.
Guest access is included with all Business Premium Office 365, Office 365 Enterprise, and Office 365 Education subscriptions.
Enterprise-grade security and compliance
All guests in Teams are covered by the same compliance and auditing protection as the rest of Office 365. Guest accounts are added and securely managed within Azure AD through Azure AD B2B Collaboration. This enables enterprise-grade security, like conditional access policies for guest user access. Azure AD also uses adaptive machine learning algorithms and heuristics to detect anomalies and suspicious incidents, enabling mitigation or remediation actions, such as multi-factor authentication, to be triggered as appropriate.
In addition, with Azure AD, IT departments have unparalleled insight into the activities of external users in their organization through detailed sign-in and access reports. Admins can centrally manage how guests participate within their Office 365 environment and easily view, add, or revoke a guest’s access to the host tenant.
you can find further information related to guest access in Microsoft Teams. Here