Iam 21yr old male n iam 5 feet 8" tall . is there any possibility so that i can increase my height?

Not likely: Unless you had a very late puberty or other underlying illness that delayed your growth, you likely have little growth left. Whatever growth you do have coming will not be helped by any treatment (even human growth hormone).

Unlikely to happen: Some kids continue to grow taller into their late teens or rarely early twenties but only when their bone maturity lags behind their age. If the growth centers of the long bones have fused, you cannot grow taller. A single x-ray of the wrist & hand can yield a bone maturity.Most boys stop at 17. When you have reached bony maturity, you are done.