This is optional.
You can publish the config-file with:
php artisan vendor:publish --provider="Rmunate\\Utilities\\Providers\\SpellNumberProvider" --tag="config"
The configuration file will prove valuable if you intend to consistently use a single target language for converting numbers into letters.
It also provides a comprehensive global output manipulation feature, empowering you to implement various adjustments or restore settings to the default package letter output.