My macbook cannot download macos. I have quit update, but it does not work. I need my mac to work, but It’s not come back to normal creen.

1 - Restart in Safe Mode. This will perform a Disk Repair, clear cache files and only load Apple Software, extensions and fonts. The boot up will be slow and can take some time - Normal.

2 - Does the issue present in this mode ?

3 - Sometimes a Safe Boot followed by a Normal Boot will just put things right.

See this Link and see if it can be of help If your Mac starts up to an Apple logo or progress bar - Apple Support

Do you have access to another Mac? If so, you can make a bootable Mac OS installer if everything went wrong.

If your Mac starts up to an Apple logo or progress bar - Apple Support

And I hope you have made a time machine backup before updating