update_user_meta(): invisible data storage

It should be stored in the wp_usermeta table under the entreprise and os user meta keys.

You should consider using prefix on your custom meta keys, to avoid name collison. Example:

kerzzy_entreprise 
kerzzy_os

It should show up with:

SELECT * FROM `wp_usermeta` WHERE `meta_key` = 'entreprise'

in your MySQL administration tool, e.g. PHPMyAdmin.

… and make sure you’re in the correct database 😉