Minecraft Java Edition – Why Special Loot Table Can Only Be Received Using /give and Not /summon

The /clone command can copy the chest and place it elsewhere:

/clone <x1> <y1> <z1> <x2> <y2> <z2> <x> <y> <z> [maskMode] [cloneMode] [TileName]

For example, if the chest you're inserting items to is at X0, Y64, Z0, and the mailbox chest is at X100, Y64, Z100:

/clone 0 64 0 0 64 0 100 64 100

Keep in mind that this requires both coordinate locations to be loaded. You can use the /spreadplayers command to forcibly load the chunks using a dummy entity such as an armor stand just before running the /clone command.

/spreadplayers <x> <z> <spreadDistance> <maxRange> <respectTeams> <player …>

/spreadplayers 0 0 0 1 false @e[type=ArmorStand,name=anchor]
/spreadplayers 100 100 0 1 false @e[type=ArmorStand,name=anchor]
/clone 0 64 0 0 64 0 100 64 100

And one other thing to note is that the contents of the mailbox will be completely replaced, so any items that were still in that chest will be deleted. A solution to that is to clone the initial chest above a hopper above the mailbox chest, such that the items will be transferred to the mailbox.

You could also use /setblock to destroy the cloned chest such that the items will be dropped instantly and do not have the risk of being deleted as well.

/setblock 100 64 100 minecraft:air 0 destroy

The issues with your command are:

1. display needs to start with a lowercase d
2. display is a compound tag - { } - rather than a list - [ ]
3. Both display and CanPlaceOn should be in the same top tag, rather than two separate top tags. E.G: {display:{...},CanPlaceOn:[...]} rather than {display:{...}},{CanPlaceOn:[...]}

Here's the fixed command:

/give @p wool 1 14 {display:{Name:"Example",Lore:["One","Two"]},CanPlaceOn:["minecraft:stone"]}