While many Android smartphones these days have software that's evolved into a robust and very enjoyable experience, that doesn't mean that there aren't still plenty of people who are willing to tweak things to make them a little more custom. To load up custom firmware, however, you'll need a custom recovery installed on your device which allows you to flash the custom firmware to your phone. Perhaps the most popular at this point now is TWRP from TeamWin, and today they have just added support for a few more phones including the recently released Xiaomi Mi MIX, which you can read up on in our full review if you want to know more about it.
While the Xiaomi Mi MIX is the newest phone of the three devices to receive TWRP support today, the others are fairly recent offerings as well. Aside from the Xiaomi Mi MIX, Honor 8 owners will have the opportunity now to install TWRP's custom recovery onto their devices too, and so will anyone who uses the K30 from Lenovo. With custom recoveries on all three of these devices, flashing custom firmware, also known as ROMs, won't be the only thing users will be able to install, as custom recoveries can be used for flashing themes, and of course the most important feature of a custom recovery is the ability to backup and restore your device which you'll want to be doing often if you flash custom firmware.
If you don't already have TWRP installed on your device, and since these three phones just gained support, they won't have it installed, then there are two methods for getting TWRP onto your phone, regardless of which of the three you have. The first is the App install method, and to utilize this particular method you'll need to have a rooted device. Rooting the phone can be done without a custom recovery, so if you feel this is the easier route, then the process is pretty straightforward and TWRP provides the steps you need to take to complete the process. The second method is the Fastboot method, which does not require root, but it may be a little more complicated if you have never used Fastboot for anything before. Again, TWRP provides instructions on using this method to get the custom recovery software onto your device. With that said, you can jump to the TWRP page from the source below, and find your phone in the list to grab the files you need.