My MacBook air only shows apple logo

Hi,

Your Mac may not be able to find a system folder to boot from.

Shut your Mac down then wait at least then seconds then restart while holding down the Option key. That should open the Startup Manager window where you can select the startup disk (Macintosh HD) then click Restart.

About the screens you see when your Mac starts up - Apple Support

Hi,

Try booting into Safe Mode: https://support.apple.com/en-us/HT201262