If your Mac doesn’t turn on
If your computer won’t turn on, make sure you plugged it into a working power outlet. If you have a Mac notebook, make sure the battery is charged.
Check power and cables: Make sure the power cord is plugged into the computer and into a functioning power outlet. If you’re using a MagSafe power adapter, the adapter light glows amber if the battery is being charged, and glows green when the battery is fully charged. Be sure to use the power adapter that came with your computer or a compatible replacement adapter. See the Apple Support article Find the right power adapter and cable for your Mac notebook.
If that doesn’t work, try another power cord or power adapter to test whether the problem is with the power supply or the computer itself.
Check the battery: If you have a Mac notebook with a removable battery, you can check if it needs to be recharged by pressing the small button on the battery or on the side of your computer. See your computer’s documentation to find out where the button is. You should see lights indicating the battery’s level of charge. If only one battery indicator light is flashing, allow the power adapter to charge the battery until at least one indicator light is glowing continuously.
Try other solutions: If you already checked the power, cables, and battery, there are other solutions you can try. See the Apple Support article If your Mac doesn’t turn on.
If you still can’t start up your Mac, it may need to be serviced. See Find how to service or repair your Mac.