my device is showing apple logo only why..its not connecting with itunes also why?

If your iOS or iPadOS device restarts or displays the Apple logo or a spinning gear unexpectedly, read this support article for how to resolve this --> --> If your iOS or iPadOS device restarts or displays the Apple logo or a spinning gear unexpectedly - Apple Support

It has you:

- Check your software

- Check your hardware

Read this support article about what to do if you can‘t update or restore your iPhone, iPad, or iPod touch, --> If you can't update or restore your iPhone or iPod touch - Apple Support

You can put your iOS device in recovery mode, then update the software. The update option does not erase your data.

In these situations, you might need to use recovery mode to restore your device:

iTunes doesn't recognize your device or says it's in recovery mode.

If your screen is stuck on the Apple logo for several minutes with no progress bar.

You see the recovery mode screen.