There it is. And then you can hold meta+click with the mouse to move it, and at that point you can grab a corner to resize anything as you see necessary.
meta+f will toggle fullscreen on anything as well. All of these are customizable to your preferences as well. Just edit the i3 config for whatever works for you. I immediately switch my kill window to meta+shift+x - I have used it for years now. I even use it as a shortcut in Plasma and basically every install I do.