Leads can be used in more ways than you might think.
Leads can be found in loot boxes, or taken from wandering traders with their llamas. They are used to tie to a specific mob and allow the player to bring that mob along.
Leads can also be used to connect a mob to another object, such as a fence or wall in Minecraft: Bedrock Edition. These are the primary functions of leads, and they’re very easy to implement.
Minecraft: How to use leads for entities
A lead can be obtained by any Minecraft player. The item will be added to the toolbar so that players can select it and place it in their hands.
Next, players will need to locate the entity or object to which they want to attach the lead. Below is a list that allows players to attach entities to leads:
Boats (in Minecraft: Bedrock Edition)
Chickens (including those being ridden by Chicken Jockeys)
Llamas (including those owned by the Wandering Trader)
Skeleton Horses (including those being ridden)
Villagers (with edited NBT Tags)
Once they have located the block or entity they wish to attach the lead too, players can simply approach the entity holding the lead and press the right-click button or the use button on other devices.
This will attach the lead to the entity. Players can then have the entity follow them. They can tie the other end of the lead to the entity by right-clicking or pressing the use button.
Minecraft players can use leads to decorate their Minecraft world by tying them together with fence blocks and walls. These handy items have been used by some players to create structures like power lines or rope bridges.