I am unable to locate the guest mode option on my mobile device. Could you please provide me with instructions on how to access it?

During night mode shoot loot of shakes and not good quality output and Normal photo shooting mode loot of shakes even though I am using tripad loot of shakes in photo ! Over all the output is not good 

Whenever I capture a selfie at night, the photographs are so captivating and the output is significantly less only in selfie camera