Which surgery is required to increase pennis size ?

No great solution: The is no surgical intervention to truely enhance or lengthen penis size. It is possible to release the pubic suspensory ligament to the penis giving the illusion of greater length. If an individual has a promenant supra pubic fat pad, weight loss will also give the appearance of increased penile length.

No short answer: Short answer without explanation: increase girth with under skin collagen or fat injection, increase appearance of length by cutting penile dorsal ligament, increase girth and width by insertion of a prosthesis but you lose sensation and any ability to go back to normal physiological erections.