Install-Module AADInternals
Import-Module AADInternals -Verbose
Get-AADIntLoginInformation -UserName <username>@<domain name>.onmicrosoft.com
Get-AADIntTenantID -Domain <domain name>.onmicrosoft.com
Get-AADIntTenantDomains -Domain <domain name>.onmicrosoft.com
Invoke-AADIntReconAsOutsider -DomainName <domain name>.onmicrosoft.com
https://login.microsoftonline.com/getuserrealm.srf?login=\@<domain name>.onmicrosoft.com&xml=1