Create New Items (Debug Items?)

@Shaw_Designs I'm not sure if I'm completely following your question, but there are two sets/levels of debug items that can be opened up – one after entering the 'bb.showhiddenobjects', and additional ones after then/secondarily entering 'bb.showliveeditobjects' (additional detail/directions, if you need those). When you enter the first of the cheats (bb.showhiddenobjects) there are many additional items in Build & Buy that open up also, including some items that are awards for careers, etc. 

The more packs you own the more items open up, also, both in hidden objects and in debug objects.

There are CC (custom content) creators that make added content for the game, but I'n not sure any of those items add themselves into debug.

Debug objects are a variety of items from the game, created by the game designers. Some of the items don't 'stick'/stay if you try to add them to your lot (for example, some types of food or other items that I assume are the 'visual' used in an action the Sim has - like a mixing bowl they pull out briefly). Some items are ginormous, some are just plain weird, some items your Sim will walk right though (there is no 'substance' to them added in the game as far as the Sim is concerned). Some items will block your Sim when it doesn't seem to make sense, and some items can be interacted with for the Sims. Many debug items are also free, and some of them are copies of items in the game with different features (a light with less light that comes from it but it's free, for instance). 

Because of all of these oddities in dealing with them, or because they are items revealed by a career, skill level, or for some other reason they are not shown initially or available to all Sims, I expect you can see why the items are not shown in your normal Build/buy items. Revealing they in the manner mentioned above is a 'cheat'. Not a cheat in the negative sense - EA has even intentionally announced the codes needed to show the items. 

I hope something here helped answer your question. Please clarify if I was off the mark. Thanks!

@Shaw_Designs , the Debug items are items that the developers have put in the game, usually in the parts of the world that aren't accessible by Sims. They are used to "fill out" the background to make it more realistic. 😎 And because they are just decorative an used in the game in areas Sims can't go, they aren't programed to act like the regular objects in the game.  So your Sim will be more likely to act like they don't even exist if you use the debug cheat and place them on your lot.  😂

However, many Simmers who are "builders" use these items in their build for the "starter homes" that they build.  These homes need to be cheap so that a starting family can afford to live there with the house fully furnished.  That often means there isn't much money left over for landscaping and clutter object inside the house (to give it a lived-in feel) without making the price of that home too expensive to be a starter home.  So by using the debug items, which are free, they can make the lot they are building on look very nice and much more realistic, and still have it be priced as a starter home. This is especially important for houses uploaded to and downloaded from the Gallery, but even if she doesn't want to upload to the Gallery she still can use these items to make her starter homes look more realistic. 🥰

On the other hand, if she wants to create her own objects, that would fall under the category of Custom Content (CC for short).  There are various CC creators... some only create for themselves while others create for the entire community.  She would have to go and google Sims 4 CC to find some (I can't give direct links here), and their might be instructions on how to create your own.  However Mods and CC can only be used on a PC or Mac, and not the consoles! 😓

A word of caution though! ❗ EA does allow CC and Mods (Mods are similar to CC but effect gameplay and are more complicated than CC which is just more like hairstyles, clothing, different chairs, bookcases, etc.) However, EA does not support Mods/CC.  They can not alter their game around what other people make for the game.  There are just too many Mods and CC items in existence to do this.  Therefore, whenever there is a game update/patch, some Mods or CC items can become outdated, and can cause problems in your game!😓  A player who uses Mods/CC must maintain their game, replacing outdated Mods & CC (or deleting them if the Mods and CC items are not updated to work with the updated game).  Most Mods and CC creators try to quickly create updated versions of these items to be compatible with the updated game 🙌, but it is still the users responsibility to download these updated CC items and Mods and to get rid of the ones that aren't working anymore. 

Also , when doing this it is very important to delete the localthumbcache.package file from your game folder (Documents > Electronic Arts > The Sims 4), since this file can retain bits of corrupted data that can mess with your game even if you got rid of all your outdated Mods and CC! 🤨

If your wife just gets a few CC items or a few Mods, it isn't that hard to do upkeep on them. 😊 But if she is wants to have a lot of CC/Mods, then it can be difficult to find the Mod or CC that is causing problems.   She will have to weigh the positives and negatives  if she wants to do this or not and for how many items she wishes to add to her game. 😉

Does she know the Degbug cheat code already?🤔
I see that @SheriGR has already given you the codes, and even explained about other hidden objects that aren't labeled as Debug even if they act a lot like the ones that are! 🥰

@Idiosyncratic53 and @SheriGR , it seems like the 3 of us were writing out reply at the same time! 🤣