Welcome to KFN. You're about to post in the Help the New Guy forum.

1) Please include the following information in your posts:
  • The version/release of Kubuntu you are using.
  • Whether Kubuntu is actually installed, or is running "live" from a bootable USB Flash Drive or LiveCD.
  • If Kubuntu is installed, is it the only OS on the PC, or is it installed alongside another OS (Windows or ...) or is it installed in a VM (Virtual Machine)?
  • The version of KDE Plasma installed.
The first and last item can be obtained by pressing Alt+F2 and typing: About this System and pressing Enter/Return.

2) Information about your PC:
  • Open a konsole and type: inxi -F --xxx
If inxi isn't installed (unlikely, but...) then type: sudo apt update && sudo apt install inxi. When installation is completed, run the command above.
  • Copy and paste the output.

This information saves everyone a lot of time (and possibly wasted effort) when attempting to assist you with your question/inquiry/problem.

Thank you.