I purchased dulingo plus las July 06 for my wifes dulingo and she never receiverd it what that gives here i have questioned this a number of times and never got a response I purchased it with her email address not mine i

Apps are tied to the Apple ID they were downloaded under, so set up Family Sharing so your wife can use the app you purchased. See this link --> Family Sharing - Apple

This link will explain Two Factor Authentication --> Two-factor authentication for Apple ID - Apple Support

I get you are frustrated, but not knowing how to use the technology on your phone doesn't mean Apple made it hard for you. And you can certainly buy other phones, but if you think that will make sharing purchases easier, think again.

You joined here today so how have you asked this question many times?

If you purchased the app with your Apple ID it will only work with her iPhone if you have set up Family Sharing. Have you done so?

Duolingo is a third party app so your question about some code and the app not working should be directed to them.

You question is extremely disjointed and rambling so I'm not going to try to address the rest of it. I suggest you buy the better smartphone that many people have told you to buy.