CWM a k a clock work recovery is a software that allows you to install custom firmwares and all sorts of hacks including ability to root HTC Desire 616. Fortunately CWM for HTC Desire 616 is now available. To install CWM on HTC Desire 616, you must use SP Flash Tool to install.
You can download it but before you use it on your computer, you must install driver for SP Flash Tool for windows. Then select MTK_AllInOne_DA.bin and then MT6592_Android_scatter.txt.
After that press download button and turn off phone (wait for it turn off completely) and plug the USB cable into phone. The SP Flash tool will auto detect your Desire 616 phone and write recovery.img into phone.