New Backpacks Add-on (1.13) !!

now for pc 1.12 : 

this for java 1.12

This is the first add-on for Minecraft: Bedrock Edition to implement fully working backpacks to the game.They are essentially a mobile chest which you can wear on your back while traveling around in your world. It’s great if you are out on an adventure and need somewhere to offload your blocks and items. It’s easy to wear and also easy to take off in case you need to access the storage space easily. It’s definitely a must have for all the survivors out there! 

How does it work?

To get a backpack you’ll need to craft one. Crafting recipes are listed below, and in the Backpack Guide screen, located in settings.

To wear a backpack simply stand near one and it’ll jump on your back. To get it off sneak and jump.

You can only open your bag by placing it down on the ground and opening it. It’s also possible to open other players bags while they are wearing them, if they are unlocked.

You can lock and unlock your backpack, to do so first you’ll need to tame a backpack with a tripwire hook, then to lock it hold a tripwire hook and hit “Unlock Backpack”. To unlock crouch and click “Unlock Backpack”. This will prevent players from stealing your items.

There’s 3 different size backpacks, all of which can be dyed by putting a brown Backpack in the crafting table, along with your dye of choice.

There’s only one way of destroying your backpack, you’ll need to crouch while holding a stick to destroy it. The backpack will NOT drop what was inside it doing this.

Small Backpacks have 9 inventory slots.

Normal Backpacks have 15 Inventory slots.

Big Backpacks have 27 inventory slots.

If you need help, check the Backpack Guide screen, located in settings.

Features

Wearable

Functional

Lockable

Tameable