You can unlock the bootloader on any htc phone through their website here:
HTCdev - Unlock Bootloader
Your device isn't listed, so you will have to select "All other supported devices" from the bottom of the drop-down menu.
Once the bootloader is unlocked you have to flash a custom recovery to the phone which will allow you to add root to the phone.
TWRP recovery is available for your device here:
TeamWin Projects - TWRP 2.6 - | TeamWin
Make sure you get the right version for your phone!!
Then you will need either
SuperUser or
SuperSU. Either one will add root to your device.
I also found this
little utility that can aid in the rooting process. It uses the same method as described above but helps get you through the process.
Honestly for rooting, I would suggest signing up to the forums for an interactive experience. It is likely you will have questions throughout the rooting process, and it's good to make sure you understand what you are about to do before you attempt to do it. Maybe you have rooting experience and this information is enough to go on.
If you decide to
Sign Up you can head over to our
One X Plus - All Things Root section to get any questions you might have answered!