Set-IndivdualUserMessagingPolicy.ps1

param(
    [Parameter(Mandatory)]
    [string]
    $UserNameToSetPolicy,
    [Parameter(Mandatory)]
    [string]
    $PolicyName
)

Import-Module "C:\\Program Files\\Common Files\\Skype for Business Online\\Modules\\SkypeOnlineConnector\\SkypeOnlineConnector.psd1"

$Session = New-CsOnlineSession
Import-PSSession -Session:$Session -AllowClobber

if (-not $(Get-CsTeamsMessagingPolicy -Identity:$PolicyName -ErrorAction:SilentlyContinue)){
    Write-warning "Unable to find Policy $PolicyName"
    return
}
else{
    Write-Information "Granting Message Policy $PolicyName for user $UserNameToSetPolicy..."
    Grant-CsTeamsMessagingPolicy -PolicyName $PolicyName -Identity $UserNameToSetPolicy
}

Remove-PSSession -Session:$session
write-Information "Done"