How can i update my iPhone 6 plus to iOS 13?

You can recycle / sell your phone and buy a new, current-gen iPhone that brings supports for iOS 13.

An iPhone 6 cannot be updated past iOS 12.4.7.

You cannot. iOS 12.4.6 is the highest possible for that model.

If your phone is at iOS 12.4.6, you can not upgrade further. If you want/need a higher version, you need a newer device.

zakaria183 wrote:

What can i throw dis phone

It is your device, if it no longer works, recycle it responsibly.