You pay however much you wish to tip someone (say up to $150, we'll have to think it over for more than that).
You give a description of who deserves the payment. The website shows this information along with the sum of the tip. The information includes images of the waiter, or a description of the
location where you are at. Usually the information will include something that only the person getting the money knows in advance, without being published on the site.
The person who deserves the tip, see's the tip on LeaveTip.com, by searching for the thing he or she deserves it for. (Say a meal at the Waldorf Astoria this evening in Jerusalem, which included Waldorf salad, and was at the corner table. The waiter's details are unknown to you, and your details are unknown to the waiter but they get their tip, and you pay it.
You can leave tips for anyone who cleans up that pile of garbage on the corner opposite the post office and sends a picture of themselves cleaning it up, and another one of the place after finishing.
The actual acceptance of the transaction is done via the LeaveTip personnel (or an AI bot at some stage when the technology gets better, or by an Overstand bot, when I finish phase I of my startapp),
The LeaveTip moto:
Money cannot buy you happiness, perhaps, <br />
but giving money can.