Change default language URL

Hello guys,

How can I make the default language with /code/ in the beginning like this website https://hqz.ro/ro/

I have this website https://itextrem.com/hqz and I want to change the default language to this https://itextrem.com/hqz/en

Example product link: https://itextrem.com/hqz/categorie-produs/bijuterii-din-aur/ to this https://itextrem.com/hqz/en/categorie-produs/bijuterii-din-aur/

The page I need help with: [log in to see the link]