Automatic Calendar Events from Outlook
Turning off “Events from Email”
Tell Microsoft they’re not helping
Single Person
By Hand
Settings (The Cog) > Calendar > Events from email > Turn all off

The powershell way
Set-MailboxCalendarConfiguration -Identity "[email protected]" -EventsFromEmailEnabled $falseThe Whole Org
There is only one way
Get-Mailbox -ResultSize Unlimited | Set-MailboxCalendarConfiguration -EventsFromEmailEnabled $false