For regular Langstroth hives, as well as other conventional box configurations, bee supply companies are happy to sell you a feeder that fits on top of the hive. I prefer ones that let you add syrup without disturbing the bees, like this one from Mann Lake Bee Supply.

For Top Bar Hives, most supply stores do not see a commercial feeder. So how do you feed the bees in a top bar? One way is to use a plastic waste bucket, cut to fit inside the hive. Fill it with floating material, such as pine needles, and you are set.

May you prosper and find honey.