Hi,
We suggest getting in touch with our technical support team through our websites since you are using the Pro/Commercial version of the plugin.
In any case, all issues you’ve reported can be easily fixed without any particular knowledge. More precisely, Hebrew is a language with many multi-byte characters, and the default PDF font installed in VikRentCar is a light-weight font definition (“Helvetica”) that doesn’t support multi-byte characters. On our website you will find the instructions to install a custom plugin on your WordPress website that will allow you to choose a specific and different font for generating the PDF documents, including the invoices, such as “DejavuSans”.
Third-level domains require a dedicated license for the Pro/Commercial version of the plugin, but if you are working on a Multi-site environment, then it’s sufficient to register the main hostname.
Lastly, translations are applied depending on your language settings as well as on the language assigned to each rental order. Headings may be specific texts available in the Configuration page, which can be translated into other languages from the apposite Translations page in VikRentCar. Even in this case we suggest getting in touch with our technical support team by opening a support ticket through our websites so that we can assist you better.
Thanks,
The VikWP Team