enternet is bad and my iphone mobile data works only on lte not even 4g how cam i change that to 4g ??

In fact, even iPhones sometimes display 4G and sometimes LTE. I believe, it depends on the provider. In some countries 4G is more commonly used than LTE. In the USA, LTE originally did not necessarily mean 4G, but in Germany, LTE and 4G have always been used synonymously. 

Hello @Ggtfddnntt please feel welcome in our comunity. 💙
You are already receive hints from Denner and Smartfön, thanks to you both.
Is your request solved or do you still need support?

kindly regards 
Michael