I have rooted my android and installed succesfully custom recovery twrp zip through flashify. Then tried to install custom rom but my device is now damaged totally, its is now getting on/off on its own and device is not starting only screen with lenovo androis is seen for now.
Did you try flashing the ROM again? It's possible that bootloop problems occur if you've not flashed the ROM properly or if you flashed the wrong one. Check of the ROM is really compatible with your phone. If it is then check if there's something wrong with the ROM file. Maybe it might not have been downloaded completely or is corrupt. Also try flashing the superSU again.
Never use flashyfy , for serious flashing at least , and a TWRP flash is a serious flash. Flashy damages flashes (maybe it’s still buggy) . I had similar problems when I used flashyfy. All the problems ended when I stopped using it.
You give very little information about your phone , your ROM and your TWRP. All that is important for us to help you effectively.
With the little information that you provided I suggest :
You flashed twrp through flashyfy (say twrp.zip or twrp.img)
Now boot into twrp and reflash twrp.zip or twrp.img (from your internal storage or microSD card)
wipe cache , dalvick cache , sysytem and data and then flash your ROM. No need to wipe internal storage and micro SD card.
Everything will work fine after this ...
In the remote chance that it doesn’t work , then use the pc flashtool to at least flash the ROM and twrp. You can also selectively flash twrp only and then flash the ROM through this twrp.