While I was working, my MacBook screen unexpectedly displayed an unusual appearance as shown in the attached picture.
I am not sure what should be done.
I tried restarting my laptop and it is still the same. Please help.
Use Apple Diagnostics to test your Mac
Described in details here
To start it depends on type of your Mac, for Intel CPU use the Turn on your Mac, then immediately press and hold the D key on your keyboard as your Mac starts up.
It should tell you if. you have hardware or sotware problem
Once you have the result come back and report it, we might be able to help further
If hardware test shows no problems lets do the Software test
Start up your Intel-based Mac in safe mode
Turn on or restart your Mac, then immediately press and hold the Shift key until you see the login window. Log in to your Mac.
You might be asked to log in again.
On either the first or second login window, you should see “Safe Boot” in the menu bar.