My iPhone can not format. Whenever I format its showing error message

Taj, try to put your phone in DFU-mode and then restore. Connect USB, hold home and power button together, after about 7 seconds the phone will turn off. Keep holding home and power for another 3 seconds, now release the power button while holding the home button for another 10 seconds. The phone should be off with a completely dark screen, iTunes should give a message that your phone is in recovery-mode and should be restored. If that does not work, you also want to try a different USB port, a different computer as well as a different cable. Use a USB port on the back of your computer not through a hub or front panel. Hope this helps, good luck.