Since your plugin is asking about the country, it would make sense that it displays proper fields in the booking forms. I need to change some fields to display Canadian terms.
State / County * field has to state Province Postcode * field has to state Postal Code
And I don’t think it is right to make your customers pay extra and even annually to be able to change fields like that. After all, you are selling this plugin to everyone not only in the USA.
Thanks for your question. It is possible to change the texts of the plugin (including the labels of the fields) by editing translations of the plugin. You may use the Loco Translate plugin to change the translations of those labels right on your dashboard.