Find When An AzureAD EntraID Tenant Was Created
Lookup when the "Global Administrator" accounts were created is usually good enough:
Get-AzureADDirectoryRole |?{$_.DisplayName - eq 'Global Administrator'} |select objectid |Get-AzureADDirectoryRoleMember |select displayname, UserPrincipalName, usertype, {$_.ExtensionProperty.createdDateTime}