Hi:
You will need to install a new storage drive, and reinstall the operating system.
Below is the link to the service manual, where you can find the hard drive removal and replacement procedure.
HP ENVY x360 15m Convertible PC Maintenance and Service GuideIMPORTANT! This document is intended fo...
You should be able to use the HP cloud recovery tool to create a bootable USB recovery drive that will reinstall W10, the drivers and the software that originally came with your notebook.
Here is an info link for how to use that utility...
HP Consumer PCs - Using the HP Cloud Recovery Tool (Windows 10, 7) | HP® Customer Support