I have Iphone 6 plus on IOS 12.4.3 and purchased AirPods Pro how do i get my iphone 6 plus up to ios 13.2 ?

If it is a 6plus you cannot.

iOS 13 - https://www.apple.com/ios/ios-13/

"iOS 13 is compatible with these devices.

iPhone 11

iPhone 11 Pro

iPhone 11 Pro Max

iPhone XS

iPhone XS Max

iPhone XR

iPhone X

iPhone 8

iPhone 8 Plus

iPhone 7

iPhone 7 Plus

iPhone 6s

iPhone 6s Plus

iPhone SE

iPod touch (7th generation)**"

NOT iPhone 6

NOT iPhone 6 Plus

You don't. iPhone 6 cannot support iOS 13, it's too old. AirPods Pro are not compatible with your iPhone.

If you want to use your AirPods Pro, you also need to buy a new iPhone first. 6s / SE and newer models are supported.