How to change the amount of storage on an iPhone? If yes, please tell me?

Is there a way to change the amount of storage on an iPhone? If yes, please tell me?

Not possible sorry

Nope. It has what it has.

I have an iPhone too and someone told me something about a separate memory card i don't know if that is true but you could look into it. Hope I could help:-)

No, it's not possible. However, you can remove files that you no longer need in order to have more space, or order an iPhone with more storage.

No.
When buying an iPhone, you need to think about how much storage you're planning on using, and buy the size appropriate.