- On your PC, launch iTunes.
- Using the Lightning cord, connect your iPhone X to your computer.
- Wait for your iPhone to appear in iTunes and then choose it.
- Go to the Summary section of the report.
- Then, on the Restore [iPhone] command, click it.
- Read the message if requested, then click Restore to confirm. As a result, iTunes will begin wiping your device and installing the most recent iOS version.
After it restores to factory settings, your iPhone should restart on its own.
Allow it to finish booting up and then you can set it up as new.