About Office365, Sharepoint
Όταν ζητάμε support από την Microsoft γνωρίζει δύο contacts τα οποία τα βλέπει και μπορεί να αλλάξει ο Παναγιώτης από το Quest-on-Cloud:

Useful URL link "Hacking" For SharePoint/one drive (Provided You have the rights)
#recycle bin
/_layouts/15/onedrive.aspx?view=5
#For second stage recycle bin
/_layouts/15/onedrive.aspx?view=13
#Site settings
/_layouts/15/settings.aspx
Understanding the 400 chars path limit of sharepoint
The red part and only the red part from the below example URL is what must not exceed the 401 character limit (the official limit is said to be 400 chars but during testing we could reach 401 chars). With characters we mean unicode characters (not ASCII chars from a UTF-8 encoding, neither ASCII chars from a URL encoding nor anything else. We tested by changing one to one some latin chars to Greek chars without any effect in the limit).
somecompany.sharepoint.com/Some%20Site/Some-Subsite/Some-Document-Library/Forms/AllItems.aspx?id=%2FA folder/some subfolder/Ένας υποφάκελος στα ελληνικά&viewid=f821a73a-95c5-4ae3-b474-982c674b7dcb
(see
https://sharepoint.stackexchange.com/questions/279883/)
Site permissions for external users
Settings -> site permissions -> Advanced permissions settings
Create group
Αν θέλουμε να κόψουμε το δικαίωμα πρόσβασης σε αντικείμενα του site
settings -> site contents διαλέγουμε αυτό που θέλουμε … settings
Permissions for this document library
Stop inheriting permissions
Προσθέτουμε ή αφαιρούμε χρήστες και ομάδες.
Settings -> site settings -> Look and feel -> Navigation
Structural Navigation: Editing and Sorting
Διαλέγουμε το αντικείμενο και πατάμε edit
Στο πεδίο audience βάζουμε την ομάδα που θέλουμε να βλέπουν το αντικείμενο στο menu τους.
Από αυτό το μέρος μπορούμε να προσθέσουμε και άλλα αντικείμενα στο menu μας.
NOT SURE WHY THAT HAPPENS
Στην περίπτωση που όταν πάμε να πατήσουμε save μας βγάλει πως δεν έχουμε access μπορούμε να κάνουμε τα εξής:
Κάνουμε refresh την σελίδα που βλέπουμε αν έχουν πετύχει οι αλλαγές μας. Αν έχουν γίνει όλα καλά. Αν δεν έχουν πετύχει πάμε:
Settings -> site settings -> Site Collection Administration -> Site collection features -> κάνουμε enable το SharePoint Server Publishing Infrastructure
How to check used storage space
Visit a site > gear icon > site settings > storage metrics (=
https://mazarsgr.sharepoint.com/_layouts/15/storman.aspx)
You will get nice reports like this were you drill down by just clicking the "sub-folders":

How to connect to SharePoint with PowerShell
Download PowerShell for SharePoint Online at
https://www.microsoft.com/en-us/download/details.aspx?id=35588Connect to SharePoint:
Connect-SPOService -Url
https://mazarsgr-admin.sharepoint.com -credential admin@mazars.gr
# test that you really have access
Get-SPOSite
How to add or remove an owner to a sharepoint site
1) Go to sharepoint
admin center
2) Search for the site you want
3)

4) Add or remove the user and hit save

How to make the admin a member(first) and owner(second) of an Office365 Group - Team Site
Install required software
See
Office365AdminWithPowershell, section about "Microsoft Azure Active Directory Module for PowerShell"
Main part
Open a
64bit powershell to Connect to Exchange Online 365 / Azure / other
$UserCredential = Get-Credential
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection
Import-PSSession $Session
After you finish you can press to log off:
Remove-PSSession $Session
WARNING: The names of some imported commands from the module 'tmp_0yan4bbz.sbz' include unapproved verbs that might
make them less discoverable. To find the commands with unapproved verbs, run the Import-Module command again with the
Verbose parameter. For a list of approved verbs, type Get-Verb.
ModuleType Version Name ExportedCommands
---------- ------- ---- ----------------
Script 1.0 tmp_0yan4bbz.sbz {Add-AvailabilityAddressSpace, Add-DistributionGroupMember...
PS C:\WINDOWS\system32> Get-UnifiedGroup | Select DisplayName, SharePointSiteUrl | Ft -autosize -wrap
DisplayName SharePointSiteUrl
----------- -----------------
IT GROUP https://mazarsgr.sharepoint.com/sites/itgroup
SMOKE https://mazarsgr.sharepoint.com/sites/smoke
TOBACCO https://mazarsgr.sharepoint.com/sites/tobacco
Seminars https://mazarsgr.sharepoint.com/sites/seminars
ΓΣ ΑΠΟΛΛΩΝ ΣΜΥΡΝΗΣ ΠΑΕ https://mazarsgr.sharepoint.com/sites/fcapollon
ΕΛΣΑΠ (1024) https://mazarsgr.sharepoint.com/sites/1024
chep https://mazarsgr.sharepoint.com/sites/chep
...
PS C:\WINDOWS\system32> Get-UnifiedGroupLinks -Identity "AOS" -LinkType Members
Name RecipientType
---- -------------
admin UserMailbox
akis.rizopoulos UserMailbox
themis.polizos UserMailbox
ioanna.athanasatou UserMailbox
dimitris.tsapogas UserMailbox
Charalampos.Tsamilis UserMailbox
emmanouil.androulakis UserMailbox
katerina.chanioti UserMailbox
PS C:\WINDOWS\system32> Add-UnifiedGroupLinks -Identity "AOS" -LinkType Members -Links admin
PS C:\WINDOWS\system32> Add-UnifiedGroupLinks -Identity "AOS" -LinkType Owners -Links admin
PS C:\WINDOWS\system32> Get-UnifiedGroupLinks -Identity "AOS" -LinkType Owners
Name RecipientType
---- -------------
admin UserMailbox
IMPORTANT: you need to wait at least 20-30 minutes for changes to take effect