Help Phone stuck on Bootloader,I googled it but no result

It sounds likely that either KingRoot or Flashify has made a mess of the system software, or maybe you've flashed the wrong TWRP build. What happened when you tried to factory reset: did that take you into TWRP, into the stock recovery, or nothing at all? If nothing that implies that the recovery is broken as well.

(Personally I'd always avoid tools like that unless there was literally no alternative: I'd just use HTC's own bootloader unlocking service (from HTCdev.com) to unlock the bootloader and use fastboot to flash TWRP).

Anyway, since we don't know exactly what's been corrupted we don't know what to reflash, so the simplest solution is to reflash the phone completely. If you can tell us exactly what model this is (M8_<something>, and what country/carrier it was originally sold from we can try to find a compatible firmware package (a ROM Upgrade Utility, or RUU). Or if you can install fastboot on your computer (you should be able to find a download from htcdev.com), put the phone in fastboot mode (it's one of the two bootloader modes), connect via usb and use the command "fastboot getvar all" and tell us what the cidnum is that will also help. Either way any software information you can get from the bootload screen (build, baseband version, hboot version) will also help, since unless you are S-Off we need to make sure the software is at least no older than what you already have (it won't install otherwise).

If you are S-On you'll need to relock the bootloader to flash the RUU (if it is unlocked in the first place).

An RUU will also unroot you and replace TWRP with the stock recovery, but on the plus side you can use it to install a newer version of android. So if that was your only reason for rooting then we can probably solve that problem in the process.