I've been looking for something this for years, but the service is missing one thing - scheduling. I have terrible hand-writing and a poor memory for birthdays

I've been looking for something this for years, but the service is missing one thing - scheduling. I have terrible hand-writing and a poor memory for birthdays. I'd like to schedule cards to be sent out, pre-writing them maybe a year in advance. It means I can sit down and write all the birthday cards in one sitting, and then forget about them. Not really in the spirit of birthday's I know. I would need to be able to cancel a card (should for example, an elderly relative die before their birthday). Where are the cards sent from? I'm wondering what stamps get put on the envelope when sent internationally.