After pressing command R it’s not working

Hello saranyaakz01,

Welcome to Apple Support Communities!

If we understand your post correctly, your MacBook is persistently showing a folder with a question mark in it. We'd like to help!

The article that you came from, If your Mac starts up to a question mark, is a good resource for the issue you're having with your MacBook.

"If the question mark persists, follow these steps:

1. Press and hold the power button on your Mac for up to 10 seconds, until your Mac turns off.
2. Turn on your Mac and immediately press and hold Command (⌘) and R to start up from macOS Recovery.
3. While in macOS Recovery, use Disk Utility to repair your startup disk.
4. If Disk Utility found no errors or repaired all errors, reinstall macOS.
5. If you still need help, please contact Apple Support."

Let us know if you have any questions.

Thank you for using Apple Support Communities.

Take care!

I tried to get my 2015 Imac to get past black screen with flashing question mark to recover and reinstall operating system. But when I did these 3 options: press power button & hold Command+R or press power button & hold Option +Command + R or press power button & hold Option + Command + P + R, nothing happens but black screen with flashing question mark.

Any ideas what is happening/reasons and what I can do from here?