Add a guest to a team
Anyone with a business or consumer email account, such as Outlook, Gmail, or others, can participate as a guest in Teams.
As an admin, you can add a new guest to the organization in a couple of ways:
Global admins or Teams admins and team owners add a guest to a team in the Teams clients or in the Teams admin center. To learn more, read Add guests to a team. If you haven't set up guest access yet, go through the steps in the Collaborate with guests in a team.
Add guests to your organization through Azure Active Directory (Azure AD) B2B collaboration. For details, check out Quickstart: Add guests to your directory in the Azure portal.
Admins can also delegate permissions to add guests to others in their organization by assigning the Guest Inviter role. For more information, see Enable B2B external collaboration and manage who can invite guests.
With Azure AD B2B collaboration, organizations can enforce conditional access and multi-factor authentication (MFA) policies for B2B users. These policies can be enforced at the tenant, app, or individual user level, the same way that they are enabled for full-time employees and members of the organization. Such policies are enforced at the resource organization. For more information, see Conditional access for B2B collaboration users. Individual guests can't be blocked.
Guests you have already added via Azure AD B2B, Microsoft 365 Groups, or SharePoint are ready to go. The Microsoft 365 admin or a team owner can add those guests to their respective teams. If you add a guest directly to the Microsoft 365 group associated with a team, the guest will get access to the team but the Microsoft 365 group doesn't generate an invitation email to the guest, so someone on the team should notify the guest.
You can track guest additions in Azure AD or the Microsoft 365 security center. Adding a guest in Microsoft Teams is audited and logged as an Azure AD group administration activity "Added member to group". For more details, see Auditing and reporting a B2B collaboration user and Search the audit log in the compliance Center.