https://www.nexusmods.com/skyrimspecialedition/mods/16977
All credit goes to Vidani, I only repackaged for Skyrim SE. Original post here.
Bag of Holding ReadMe
v2.0
If you are updating - first launch after updating will remove your old bag and add a new one (all your stuff will still be there).
-Changed appearance of the bag to something more fitting.
-Improved the script
-Removed the constant running quest script
-Craftable at forges
-Can be activated from the Favorites Menu without Hotkeying
-Can be activated from the Item Menu
-Can be activated after being dropped
These changes were made in a big part with help from JustinOther
http://skyrim.nexusmods.com/users/535437
The "Bag Of Holding" is automatically added (craftable after 2.0) to the player's inventory on game load, just to make things simple. There are several ways to activate your BOH, one is to hot key (must be favorited), and the other is to grab the BOH as if to move it. The BOH will not equip from within the Item Menu at this time, and has a failsafe in case of accidentally adding the BOH into the BOH.
The BOH acts as any non-respawning container and will hold all your items. The BOH can be dropped from your inventory and placed anywhere in the game if you should not want it in your inventory for any reason.