I am well thorough with the concept of virtual and real images for a single lens/mirror. However I don’t understand how it exactly works for complex system of lens .eg-two or three lens with a silvered surface. If the image formed by the last element (lens/mirror) is real ie. rays actually meet to form an image, can we claim that the entire system produces real image?
Yes, the terminology for lens systems is the same as for single lenses, at least if you're only interested in the element as a whole. It may produce real/imaginary intermediate images between the elements, but if the rays coming out the end cross to make a real image, you can say the whole element produces a real image.