Inviting/Adding External Users to Modern Team Sites

Hi - there are a couple of resources that describe how to enable/manage external users for Office 365 Groups:

1. Guests in Groups:  Allows you to configure ability to add guest members to the group, giving access to the full set of group resources
2. External Sharing for group sites:  The article is linked to a broader page on PowerShell admin/management of Office 365 Groups, but there is a section that calls out how to enable external sharing for sites connected to Office 365 Groups.  Note that the default for group connected sites is to only allow sharing with external users that already exist in your organization's directory.  See example (pasting relevant section) below.  Note that we are planning on changing the default for this setting to enable external sharing:

Manage external sharing for Office 365 Group site collections

By default, all SharePoint site collections that are part of an Office 365 Group have the sharing setting set to Allow sharing only with the external users that already exist in your organization’s directory. To change this setting, you can use the Set-SPOSite Windows PowerShell cmdlet.

Example:

Set-SPOSite -Identity https://contoso.sharepoint.com/sites/site1 -SharingCapability ExternalUserSharingOnly 

This example updates the external sharing capability of the site collection "https://contoso.sharepoint.com/sites/site1" to allow sharing with authenticated external users. This cmdlet is executed immediately.

To view the existing sharing setting, use the Get-SPOSite Windows PowerShell cmdlet.

Example:

(Get-SPOSite -Identity https://contoso.sharepoint.com/sites/site1).SharingCapability

For detailed information about these cmdlets and their parameters in Windows PowerShell, see Set-SPOSite and Get-SPOSite.