Verizon was the first US carrier to get the HTC One M8 on its airwaves, if only by a nose. Even so, it took the folks at Team Win Recovery Project a little longer to get their much-loved TWRP custom recovery onto the Verizon version of the phone, probably because it takes a little more effort to get around the carrier's locks. But whatever the reason, it's here, and ROM aficionados on Big Red will surely be grateful.
In order to flash the custom recovery you'll need an unlocked bootloader, which isn't as easy as most HTC hardware (because Verizon hates you). The current standard method is to use Justin Case's WeakSauce M8 root and the Firewater S-Off tool. This is some complex tinkering, so be aware that there's a definite possibility that you can brick your phone and void your warranty in one fell swoop. If that doesn't dissuade you, this handy XDA post has everything you need in one place. Once that's done, you can install it via fastboot, ADB, or via this GooManager app from within Android itself.
There are already some exciting things happening in the One M8 aftermarket scene, including a conversion of the standard GSM model into a Google Play Edition. That particular tweak probably won't work for Verizon's CDMA phone, but at least one user is already working on a "clean" GPE ROM. By the way, if ClockworkMod recovery is more your speed, there's an unofficial build of that available as well.
Source: Team Win Recovery Project