I can’t upgrade the sistem to ios 13

I cannot read the information in the image, however it would seem that you are attempting to update over the air. In that case, see this support document for help. Get help with over-the-air iOS updates - Apple Support

If that does not work, connect the iPhone to the computer and the latest version of iTunes.

You need to explain what it is that you tried to do and what happens when you tried. There would be a reason you could not update, but what happens when you try will help to troubleshoot that.