I get a question mark on my macbook

The folder with the question mark indicates the Mac cannot find a valid OS to boot from, likely due to corruption of the OS volume or a drive failure.

If your Mac doesn't start up all the way - Apple Support 

You’ll need to restart you Mac in Recovery mode and run Disk Utility > First Aid to see if the problem can be corrected.

Restarting to recovery mode can sometimes be a little tricky as for timing the keystrokes. And it's best to do this with a wired USB keyboard. Borrow one if you have to.

I've found what works best and most consistently is to press the power button on the Mac, and then when you hear the startup chime press and hold Command-R (⌘R) until you see the Apple logo and progress bar. At that point you can release the keys and let the Mac finish starting up.

If you have attempted ⌘R recovery startup more than a few times without success, then you may have a situation where the internal drive of your Mac is failing or failed. Try restarting into Internet Recovery mode using Option-Command-R or Shift-Option-Command-R. You will need a solid wi-fi connection, or better yet, an ethernet cable connection to your router for this.

Mac startup key combinations - Apple Support 

About macOS Recovery on Intel-based Mac computers - Apple Support 

• Once in recovery mode and presented with the macOS Utilities window, select and launch Disk Utility.  In DU, click View > Show All Devices.  

• Now, from the list on the left, select the lowest volume that is still an indented item of the topmost internal device. It'll likely be named Macintosh HD or Macintosh HD - Data.  Then click the First Aid button and let DU check and repair the volume if necessary.  Do this to the other volumes and containers on the device, working your way up. Finally, run First Aid on the device itself.  When DU indicates the tasks complete, quit the app and restart the computer.

With any luck this will allow your computer to restart properly.

Also, please see:

How to repair a Mac disk with Disk Utility - Apple Support