i can run citra.tar.xz
tar.xz is a compressed file archive that needs to be extracted before the application can be run. Ideally you should just use the installer from the official download page: https://citra-emu.org/download/
official download page last version crash in ubuntu 16.04 dont open
sorry bad english
We don’t support 16.04 officially anymore. You will have to build it yourself I think.
16.04 is not supported. You will have to upgrade to 18.04.