If your Macbook won't boot up, don't panic. There are a few simple steps you can take to get your device up and running again. First, press and hold the power button on your Mac for about 10 seconds. Every Mac has a power button.
On laptops that have Touch ID, touch and hold Touch ID. If your Mac is still having trouble booting up with the current operating system, you can try reinstalling a new one. Restart your Mac and hold down Command + R when it boots up again. This will take you to MacOS Recovery.
Select “Reinstall MacOS” and your Mac should download and install the macOS that's right for you.If these steps don't work, you may need to take your Mac to an Apple store or authorized repair shop for further diagnosis. The technicians there can run various checks and make any necessary changes to get your iMac, Mac mini, MacBook Air or MacBook Pro up and running again.