I have a very small chin and very broad small face i want to increase my chin size.

Hello and thank you for your question. Unfortunately, I don't believe there are any specific exercises you can do to try to improve the appearance of your chin. In many instances patients require surgery such as either a liposuction procedure along the lower jawline and neck or potentially insertion of a chin implant. I would recommend you seek out an opinion regarding this with a qualified board certified plastic surgeon in your area.

Hello dear
Thanks for the question and provided information as well. 
My recommendation for you is a personal consultation with a certified plastic surgeon to be able to make a complete evaluation and suggest the procedures that can fulfill your expectations and provide you with the best results.
Good luck :)

I am not aware of any exercises that can help a small chin.  Often times a chin implant or genioplasty is indicated.  I have had success with volumizing fillers to increase chin projection, but this generally works best in patients with minor chin recession.  I recommend that you consult with a local board-certified facial or general plastic surgeon.