I haven’t got the iso13

Likely because as your signature says, you have an iPhone 6. iPhone 6 cannot run iOS 13. It has 1 GB of ram and iOS 13 requires at least 2 GB of ram. iPhone 6 has reached the end of the line as far as iOS updates go. If you want iOS 13, it's time to get a newer iPhone capable of running iOS 13.

And you won't get it until you buy a newer phone.

It requires a 6s or newer. Your iPhone 6 Plus is not compatible with iOS 13.

Because you have an iPhone 6 Plus, which is not compatible with iOS 13.