Translating CUSTOMIZATION section

Hello, I manage 2 websites with Polylang and JupiterX theme. In one of them I can change the language in the customization section (to translate for example the title of the website), in the other one I don’t have this option. Can you please tell me what I missed?
You can see the difference here:
The website with the option: https://www.dropbox.com/s/deywjuhwfl5tu42/Dostosuj%20%E2%80%9E%C5%81adowanie%E2%80%A6%E2%80%9D%20-%20Google%20Chrome.jpg?dl=0

The website without the option https://www.dropbox.com/s/qggq6a18i9accqu/Dostosuj%20%E2%80%9EHatiroo%20-%20system%20obiegu%20dokument%C3%B3w%E2%80%9D%20-%20Google%20Chrome.jpg?dl=0

Thank you in advance,
Beata

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