Dashboard, a longtime Mac feature that Apple has been phasing out for the last few years, has been eliminated in macOS Catalina and it is no longer available for use.
The Dashboard option, first introduced in OS X 10.4 Tiger, used to be a prominent Mac feature, housing sticky notes, a weather interface, a clock, a calculator, and other customizable widgets.
It was disabled by default starting in macOS 10.10 Yosemite, and in the current version of macOS, Mojave, it’s still disabled unless you seek it out, enabling it as part of Mission Control or adding it to the Dock.
Read more at MacRumors.com