Does Kliently separate billable hours from non-billable ones?

Yes. Every entry carries a billable status, and you can filter the daily and weekly views by it. That keeps internal work — admin, learning, your own marketing — out of what a client eventually sees.

When you convert unbilled time to a draft invoice, only the billable, not-yet-invoiced entries come across. Non-billable time still lives in your records for your own reporting, but it never accidentally lands on a client's bill. Mark status as you go, or fix it in bulk later.