That's called a Veil Tail Betta. I would do as much research as you can before you start. We spent a good few months reading up and asking as many questions as possible before we started.
It's usually advised not to breed once over a year old if your Betta is shop bought, as he could have been quite old when you got him. Also think about what you would do with all the babies. Have you got a shop nearby that would take them from you?