You can find the option to summon your vault on your Player Menu.
respond ONLY to you, no one else will be able to open it.
When you put into the vault an item that is already inside of it (items must be identical for this to apply), the stack of that item inside the vault is increased (so it won't create another item, it will simply increase the stacks of that item inside the vault, this will drastically reduce performance issues for vaults with many items)
Items with different stacks won't be stacked, same for items with different plot flag, vengeful properties and so on
Items stolen with the PickPocket skill can't be stored until the stolen flag gets removed
Sequencer robes are never stacked (you can check spells for each robe by examining the item)
store any kind of item (only a few can't be stored, like player corpses, some plot items, etc.)
associated with your CDKeys and can be loaded from any character you have inside
be damaged or destroyed.
some simple and effective security systems: it will save itself automatically
if: you log out without saving it/you get too far/you change area/ you-it get
attacked/a module reboot is coming.
NOTE: You can't summon your vault while you are polymorphed, and you can't polymorph while your vault is out (simply to reduce CPU load on specific occasions)