For the longest time, Minecraft did not have a fast way to transfer items. If you had an automatic farm set up for some resource (be it a garden, Cobblestone, or whatever), you used to be required to transfer items from one area to another manually. That is why Mojang created the Dropper, an item that looks very similar to a Dispenser but has a slightly different use. Here is how to make your own Dropper and how it works.
Making a Dropper in Minecraft is quite easy. All you need is seven blocks of Cobblestone and one Redstone Dust. If you are using the recipe table, place the Redstone Dust in the middle bottom slot and the Cobblestone in the remaining outside boxes. The center area should be blank for making this block. It should look like the image below.
Using the Dropper is kind of like a combination of a Dispenser and a Hopper. The Dropper will drop items from its inventory, but instead of using the block or firing a projectile like the Dispenser, it drops the version of the item that players can pick up. For example, if you place a Water Bucket in a Dispenser, water will flow out. A Water Bucket in a Dropper will only drop the Water Bucket item.
If any container item is placed in front of the Dropper, it will dispense that item directly into that container. This is useful for automatically transferring items from one chest to another without needing the resources to craft a Hopper. Still, unlike the Hopper, the Dropper needs a Redstone charge running through it to move items.