How to show date and complete time on the Ubuntu Top Panel
# Step 1) Launch ‘Terminal’.
# Step 2) Enter the following command and press enter to install dconf-editor.
sudo apt install dconf-editor
# Step 3) Go to “Activities” and launch “dconf-editor”
Step 4) Carefully navigate to org/gnome/desktop/interface. Turn on the “clock-show-date” and “clock-show-seconds”.
# You should instantly see the day, date, and time including seconds, in the top bar.