I have iPad 3rd generation how do i get the latest update

You don’t.

All over 7, 8, 9-year old iPads, like your iPad 2 OR 3 are simply too old to run anything more than iOS 9.

The internal hardware in these devices are too old, underpowered and completely incompatible with any current and future versions of iOS.

Sorry. It is what it is.

If you need/want an iPad that can run the latest and greatest versions of iOS, as well as, the most current apps available, then, you will need to purchase a new iPad from Apple or a discounted, refurbished iPad from Apple’s Refurbished & Clearance section of Apple’s Website.

Best of Luck to You!

Unfortunately your iPad is too old for new updates. IOS 9 is probably the latest version you can get.