Please provide clarity about use of Compose for Desktop and Compose Multiplatform

When  creating a Kotlin Desktop App, I am given a choice of Compose Desktop(which is what I select), but there is no choice for Compose Multiplatform(which provides the @Preview to see app with multiple type screens/devices). The @Preview would be nice to use as I develop my Desktop app to ensure good representation on various type screens. How do I change my settings from Compose Desktop to Compose Multiplatform? Is there any negative for doing this? Is it recommended not to do this?