Android recovery is a bootable partition, which lets you apply official system updates from SD Card, factory reset your phone or wipe its cache partition.
How to enter Alcatel Idol 3 (5.5) recovery mode ?
Power off your device.
Boot in recovery mode by pressing and holding at the same time.
Release all buttons when the Alcatel Idol 3 (5.5) screen flickers and in a few seconds the Recovery screen will appear.