Sorry, I want to ask, does the function "Add number as item list column option" mean to sort multiple documents? I used the method you mentioned, but it's not what I thought. I think I misunderstood this function. I'm sorry.
Sorry, I'm not sure what you mean. Number is just a regular item field like any other — it's called various things in different item types, always with "Number" in it (e.g., Patent Number). You can sort your items with it like any other column.
https://www.zotero.org/support/sorting