Office 365 Disable Junk Email Filter For all Users

$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection

set-executionpolicy remotesigned

Import-PSSession $Session

Get-Mailbox

Get-Mailbox | Set-MailboxJunkEmailConfiguration –Enabled $False