I am 25 with 5"3 height and 50 kg weight my father's weight is fine . how can i increase my weight?

You are fine: 110 pounds for a 5ft 3 in person is not a medical concern. I would question why you want to gain weight. Gaining weight is primarily a matter of putting in to your body more calories than you burn. Additional protein if you are working out should increase muscle mass. If you cannot gain, then perhaps a search for underlying metabolic diseases ought to be started.