My Macbook air M1 display left side shows vertical bar

This is most likely a hardware issue I am afraid. Please try and start the Mac in the safe mode to see if the issues persist and to rule out external software error

1. On your Mac, choose Apple menu  > Shut Down.
2. Wait for your Mac to shut down completely. A Mac is completely shut down when the screen is black and any lights (including in the Touch Bar) are off.
3. Press and hold the power button on your Mac until “Loading startup options” appears.
4. Select a volume.
5. Press and hold the Shift key, then click Continue in Safe Mode.
6. The computer restarts automatically. When the login window appears, you should see “Safe Boot” in the menu bar.

if the issue persist it most likely be a hardware issue, please Contact - Official Apple Support to set up hardware service for your Mac