You have already asked this.
I tried to help you in your original post, but your information was confusing and I could not reproduce your problem. After I made six replies to you, the conversation went around in a circle so I gave up.
Now your screenshot has changed from woocustomizer strings to feemius strings. So are we discussing translations of the Freemius strings now? I mentioned these twice previously and you made no comment about them.
If you’ve clicked the Italian translations that are bundled inside the Freemius folder, do not edit them. Your changes will be overwritten when you update the plugin.
If you need to create custom translations of the Freemius strings, then firstly you need to configure your bundle to know what these files are. This is documented. You will have to click “Add set” to add an additional text domain to the plugin. Then you’ll be able to click “Add language” for Freemius strings.
However, none of this is related to your initial problem with woocustomizer strings which I still cannot reproduce. Clicking “Add language” for the main plugin domain does not require any configuration and works for me just fine.
