What feature is often added to IDs to keep them secure?

Ultraviolet (UV) text and features are often added to IDs to keep them secure. These features are not easily visible under normal lighting conditions but become visible when exposed to ultraviolet light. This makes it difficult for counterfeiters to replicate or alter IDs without the necessary UV technology. UV text and features can include invisible ink markings, holograms, or other security elements that are only visible under UV light.