BLU Studio 7 II is an unlocked GSM smartphone with a 7-inch, 600 x 1024 resolution LCD display, and runs Android 5.0 Lollipop. The phablet was released in August 2015 .
I'm not familiar with that model, but in the camera app you may need to enable the "Flash: on" mode. Most cameras operated in a "Flash: auto" mode in which the flash will only work in low light situations.