1. V I S I B I L I T Y
It is a measure of the distance at which an object or light can be clearly discerned
REASONS FOR VISIBILITY:
When light gets reflected from the object, the reflected light enters our eye retina and thus we are able see that particular object from which light was reflected from.
In our daily life, we see certain things which are transparent, they appear transparent because most of the light is refracted instead of getting reflected.

2. CAN WE CREATE INVISIBLE THINGS
Invisibility is the state of an object that cannot be seen.
Creating something perfectly invisible obviously means that it reflects no light and every light ray passes through it. If it would absorb all the light, then it could be easily distinguished from its background. So there are kind of 3 possibilities
You create something that blends and camouflages in the background
You create a smart object that detects its surroundings and if a light ray touches it, it absorbs it and then emits it from the other side following the path of the light.
As already mentioned above, under certain conditions its easy to make something invisible. But to make something invisible in every surrounding would require artificial intelligence as well.

3. To become invisible, an object must do two things:
It has to be able to bend light around itself, so that it casts no shadow, and it must produce no reflection. While naturally occurring materials are unable to do this, a new class of materials called metamaterials is now making it possible.
Bending light around an object requires a material to have a negative refractive index. The refractive index is a property that dictates how light passes through a medium; it’s the reason a stick will look bent when placed in water.
If water had a negative refractive index, it would make the stick look as though it were bending back on itself.

4. The camouflage fabric ‘ that can make soldiers INVISIBLE
Making use of a real-time image displayed on a wearable display, it is possible to create a see-through effect. This is known as active camouflage.

5. Technology can be used theoretically or practically to render real-world objects invisible
Stealth technology is declared to be invisible to radar, all officially disclosed applications of the technology can only reduce the size and/or clarity of the signature detected by radar. With stealth & Without Stealth

6. CLOAKING "cloaking device" is used to make objects invisible
This is acomplished by manipulating the paths transversed by light through a noval optical material known as metamaterials
These materials direct and control the propagation and transmission of specified parts of the light spectrum and demonstrate the potential to render an object seemingly invisible.
Metamaterial cloaking based on transformation optics describes the process of shielding some thing from view by controlling Electromagnetic Radiation

7. How to Make an Object Invisible