Item spawn in the oven?

I would like to know how I can use a command in minecraft to give myself an oven where an item is then such as a shulker box or something?

One can also dur

/ give name minecraft: name of the item

Give the item yourself

I mean that there's already an item in the oven

I don't know anything about that

You can use McStacker for this: https://mcstacker.net/

Here is an example in which all slots are filled:

/ setblock ~ ~ ~ furnace {Items: [{Slot: 0b, id: "minecraft: acacia_log", Count: 1b}, {Slot: 1b, id: "minecraft: birch_log", Count: 1b}, {Slot: 2b, id: "minecraft: black_shulker_box", Count: 1b}]}