Hi fatemeh q,
Thank you for your purchase.

Export tools that we are using for the charts and tables are based on a 3rd party HTML5 library so there are some limitations on their side.
If you have any example please share it with use so we can take a look. We will gladly add your suggestion in our TODO list and hopefully we can implement it in some of our future versions.

As for the translation of the plugin unfortunately Persian language is not yet supported.

But if you want to translate the plugin you can read our blog post about translation and localization to get a clearer picture of situation. If you want to be able to customize all strings from our plugin you can use approach from that blog post. 

Best regards.

Hi fatemeh q,

can we export just pdf and remove png, jpeg .... from chart exporting in dropdown menu?

Something like this will require some code customization of the plugin, if you are interested we can offer you our paid customization service where you can hire one of our developers to implement this feature for you. Our price is 50$/hour.

is it possible to define a maximum length to show at the first glance in the chart? 

You can take a look at our documentation about wpDataChart callbacks where you can see how you can customize the charts. There are APIs for all of the chart engines and some examples how you can develop some callback to customize the chart to your needs.

Best regards.