I am not able to zoom in the camera. Is the default model like that or has it got to do with something with my device? Is there any solution to that?
According to this you can't zoom through official camera app on Lumia 535.
Unfortunatelly Microsoft Lumia 535 and Lumia 535 Dual SIM phones don’t support zoom in/out when taking pictures with the default camera application. Some of the 3rd party camera apps may support this functionality but the picture quality will suffer when zooming in as the device has no hardware to support that function.
This "defeat" is related to software (digital zoom, not optical), so try use other apps like Camera360 Sight.