Script for listing all groups with owners and members in Office 365.
Added count of groups left to process to see progress when running scripts in large environments.

Run either:

Get-UnifiedGroup | Get-Member
or
Get-UnifiedGroupLinks | Get-Member
to see what other properties you get add to the report.

The script creates one CSV file for information about all members/owners in each group and a CSV file for group names with number of owners, members and external members.

Read more:
Get-UnifiedGroup
Get-UnifiedGroupLinks

#Create $Info array.
$Info = @()

#Create $GroupInfo array.
$GroupInfo = @()

#Collects all groups and specified properties
$Groups = Get-UnifiedGroup | Select-Object Alias,Accesstype,ManagedBy,PrimarySmtpAddress,Displayname,Notes,GroupMemberCount,GroupExternalMemberCount,WhenChanged

#Counts number of groups.
$GroupsCount = ($Groups).count

#Creates a input to $Info for evry owner and member of each group.
#First inputs evry owner of the group, then evry member of the group.
#Creates a input to $GroupInfo for each group.
foreach($Group in $Groups) {

    Write-Host -Object "Number of Groups left to process $GroupsCount" -ForegroundColor Green
    $Members = Get-UnifiedGroupLinks -Identity $Group.alias -LinkType members
    $Owners = Get-UnifiedGroupLinks -Identity $Group.alias -LinkType owners
    $OwnerCount = $Group.ManagedBy

    $Object=[PSCustomObject]@{
        Group = $Group.Displayname
        NumberOfOwners = $OwnerCount.count
        NumberOfMembers = $Group.GroupMemberCount
        NumberOfExternalMembers = $Group.ExternalMemberCount
    }
    $GroupInfo+=$Object

    foreach($Owner in $Owners){
        $Object=[PSCustomObject]@{
            Name = $Group.Displayname
            Group = $Group.Alias
            Email = $Group.PrimarySmtpAddress
            UserName = $Owner.name
            NumberOfMembers = $Group.GroupMemberCount
            MemberOrOwner = 'Owner'
            NumberOfOwners = $OwnerCount.count
            GroupType = $Group.AccessType
            ExternalMemberCount = $Group.GroupExternalMemberCount
            WhenChanged = $Group.WhenChanged
            Description = $Group.Notes
            }#EndPSCustomObject
        $Info+=$object
    }

    foreach($Member in $Members){
        $Object=[PSCustomObject]@{
            Name = $Group.Displayname
            Group = $Group.Alias
            Email = $Group.PrimarySmtpAddress
            UserName = $Member.name
            NumberOfMembers = $Group.GroupMemberCount
            MemberOrOwner = 'Member'
            NumberOfOwners = $OwnerCount.count
            GroupType = $Group.AccessType
            ExternalMemberCount = $Group.GroupExternalMemberCount
            WhenChanged = $Group.WhenChanged
            Description = $Group.Notes
            }#EndPSCustomObject
        $Info+=$object
    }

    $GroupsCount--

}

$Info | Export-Csv c:\script\Info.csv -Encoding utf8 -NoTypeInformation -NoClobber
$GroupInfo | Export-Csv c:\script\GroupInfo.csv -Encoding utf8 -NoTypeInformation -NoClobber