creating a "sent items" folder

Perfect mail application that works simultaneously with all my accounts, a very small problem, I cannot create a “sent items” folder on the orange account although I specified that each item should be put in the sent items folder, it’s a problem because I’m never sure that the answer was effective, do you have an idea to help me?

You can’t create folders in K-9, you have to do that in the (web) interface of your email provider.