Hi Polina,
I use QTranslate for my WP translations – I think it′s the best translation plugin for WP.
https://www.qianqin.de/qtranslate/
So if you use this plugin, you can enter e.g. a multilingual label in the FS contact form settings like this:
<!–:de–>Firmenname<!–:–><!–:zh–>公司名<!–:–><!–:en–>Company name<!–:–>
