Selling 3D renders to clients for sales and marketing purposes

Hey Unreal-Team,

I’m a 3D freelancer and specialized in the field of 3D garments. I create garments for my clients for sales and commercial (Marvelous Designer) and want to enrich my work by providing photo-realistic renders created in UE (including the use of Megascan assets and MetaHumans). If I create images or videos for clients, do I or they have to pay royalty for this? They use the results to sell real garments on their website, in a catalogue (digital and print-out) or on social media.

Best
Sophie