Can we use free assets on marketplace for commercial purpose
You can use all free assets created by Epic Games for commercial purpose and for what you want as long as you use them inside Unreal Engine. About assets created by others people, all depend on the licensing. (Creative Commons, Royalty Free … )
Can i use Epic Games asset pack: Open World Demo Collection in Epic Content - UE Marketplace
For selling developed assets by my team on the marketplaces?
Exactly how do we know what type of licensing is used on any independent asset pack?
In short, the way I understand it:
In general, yes, you can use the free assets from the marketplace for games you make and sell using Unreal Engine, and for movies you render out of Unreal Engine.
You cannot use the assets to make some other kind of pack/content you redistribute (no matter whether for money or not,) and you cannot use the free assets for games or movies that don’t use Unreal Engine.
Paid-for assets may come with different licenses, depending on the creator, but many of the paid-for assets have a very similar license to the above.
For any particular use in any particular jurisdiction, you need to read the specific legal text of the license agreement and have your legal professional advise you on the specific use.