Ok, here are the steps you can follow to reinstall macOS:
- Turn off your Mac and then turn it back on while holding down the Option key.
- When the Startup Manager screen appears, select the Options icon.
- From the macOS Utilities window, select the Reinstall macOS option, and then click Continue.
- Follow the on-screen instructions to select your disk and begin the installation process.
Note: If you don't see the Macintosh HD partition during the installation process, you may need to create a new partition by selecting the Disk Utility option from the macOS Utilities window. From there, you can select your hard drive and click on the "+" button to create a new partition. Once you've created a new partition, you should be able to proceed with the macOS reinstallation process.
It is also important to note that reinstalling macOS will erase all the data on your Mac's hard drive. Therefore, it's essential to have a backup of all your important data before you begin the reinstallation process.