Apple in iOS 18 has added a new multicolor swatch to the Font & Color customization options on the Lock Screen, so now you can display the time in rainbow colors against your chosen wallpaper.
Unlike the other color swatches, the multicolor option does not currently apply to widgets and the date, which turn white when the rainbow effect is applied. However, there's a good chance this is something Apple intends to implement but has not yet got around to doing so in the developer beta.
iOS 18 also allows users to change the two Flashlight and Camera shortcut buttons on the Lock Screen to an action of their choice for the first time.
The ability to change these Lock Screen controls is part of a wave of new customization features in iOS 18, which includes app icon color-changing capabilities and more. The first public beta is set to arrive in July and the official release of iOS 18 is scheduled for the fall.
Source: Macrumors