If you want translate language for module Product Designer App. You can translate from file supported by opencart like other module.

Before translating. You need to open your language file using cPanel or ftp to edit. Next, you can follow the instructions based on your version below:

Opencart version 3.x.x.x: #

With opencart version 3x.x.x. You need open file from path:

Admin: root/your_admin_folder/language/en-gb/extension/module/pdapp.php

Front: root/catalog/language/en-gb/extension/module/design.php

Opencart version 4.x.x.x: #

With opencart version 4x.x.x. You need open file from path:

Admin: root/extension/productdesignerapp/admin/language/en-gb/module/pdapp.php

Front: root/extension/productdesignerapp/catalog/language/en-gb/module/design.php

-> edit your language you want and save.

If you want add new language. You can copy language file to your language folder.