First, I don't understand anything about Macs. My company sends me one, I press a black button on the top right accidentally and now I have a nice padlock icon asking for a password.
After some googling I find out this:
You might see the lock icon at startup if you try to start your Mac from another volume like an external drive or macOS Recovery.
Ok, nice. So how can I start from the correct volume?
It sounds like you were at the FileVault login screen, where there’s a prompt to press that button if you’re having trouble to be taken to recovery.
As you have a firmware password set, you will need to enter this to continue.
It’s not possible to change the startup disk without entering the firmware password.
If you press and hold the startup key for an extended period on newer macs, that puts it in recovery mode. From there you would hold the startup until the mac powers off.
Then connect to power and open the lid and if needed, press briefly the power button and let go. The system will boot from any available startup disk without needing to press any keys.
Here are startup keys if you need to navigate things further. Without knowing your macOS version, model / processor type, how the company set up the Mac - we may not have all the information to help you avoid calling them for direct support.
Booting into Recovery mode normally does not display a padlock, nor does it ask for a password.
Apple's Support pages show this image for when a Firmware password has been set. This prevents anyone without the password from 'tinkering' with the Mac, outside of normal running.
If you don't know the password, you need to contact your company's IT department.
You may still be able to restart the Mac and trigger normal boot-up. Hold the black button down for 5 seconds, until the Mac goes 'dead', and then restart.
