Languages switcher in the menu

Hi team,

I’d like to display the languages swticher in the menu bar.
In some topics, some people tell there is a check box called “Displays a language switcher at the end of the menu”.
I’ve searched in Dashboard/Settings/languages but I didn’t find it

here is my website : http://nicolier-evelyne.ch/

thanks in advance for help

https://ww.wp.xz.cn/plugins/polylang/