Exchange-Online

Find Mailboxes a User has Access to

Get-Mailbox -RecipientTypeDetails SharedMailbox -ResultSize:Unlimited | Get-MailboxPermission |Select-Object Identity,User,AccessRights | Where-Object {($_.user -like 'Enter email here')}|Export-Csv C:\Temp\sharedfolders.csv -NoTypeInformation

Get Mailbox Details

 Get-MailboxFolderStatistics -Identity 'Enter email here' | Select-Object Name, FolderPath, Foldertype

Get User’s Calendars

 Get-MailboxFolderStatistics -Identity 'Enter email here' -FolderScope Calendar | ft name

Get Calendars a User has Access to

Get-Mailbox | ForEach-Object {Get-MailboxFolderPermission $_":\calendar"} | Where {$_.User -like “*Enter user name here*”} | Select Identity, User, AccessRights

Get Distribution Groups and Members

Just connect to Exchange Online and run this

$groups = @()
foreach($group in (Get-DistributionGroup -Resultsize Unlimited)) {
    $obj = [psobject]::new()
    $obj | Add-Member NoteProperty Group $group.Name
    $obj | Add-Member NoteProperty Members ""
 
    foreach ($member in (Get-DistributionGroupMember -Identity $group.Guid.Guid | Sort-Object PrimarySmtpAddress)){
        $mem = [psobject]::new()
        $mem | Add-Member NoteProperty Name $member.Name
        $mem | Add-Member NoteProperty Email $member.PrimarySmtpAddress
        $obj.Members += "$($member.Name) - $($member.PrimarySmtpAddress)`n"
    }
    $groups += $obj
}
$groups | Sort-Object Group | Export-Csv -NoTypeInformation -Path "C:\temp\distros.csv" -Force

Get Mailbox Info template. Adjust as needed

# Gets mailboxes based on filter
$mailboxes = Get-Mailbox | Where-Object {$_.RecipientTypeDetails -eq "UserMailbox"}
 
$mailbox_collector = @()
 
# Creates new object with specified data about each mailbox
$mailboxes | ForEach-Object{
        $mailbox_details = [PSObject]::new()
        $mailbox_details | Add-Member -MemberType NoteProperty -Name "Mailbox" -Value $_.DisplayName
        $mailbox_details | Add-Member -MemberType NoteProperty -Name "Retention Policy" -Value $_.RetentionPolicy
        $mailbox_details | Add-Member -MemberType Noteproperty -Name "Mailbox Type" -Value $_.RecipientTypeDetails
        $mailbox_collector += $mailbox_details
    }
$mailbox_collector