The DeepL plugin included with Help+Manual uses DeepL's amazingly accurate artificial intelligence translation system to translate in both directions between English, German, French, Spanish, Portuguese, Italian, Dutch, Polish and Russan. It is very fast and works in a way that allows you to check the translations as you go and make any necessary corrections.
How to use the translation plugin
You can test the quality of DeepL translations free of charge on the DeepL website. If you wish to use it on an ongoing basis and in Help+Manual you need to purchase a DeepL Developer API subscription for the service. This is very reasonably priced, starting at just €4.99 a month at the time of writing.
Important: You must have an API key, not any other type
The only subscription type you can use with third-party tools like Help+Manual is the DeepL API key. Please do make sure that is the one you get, because other subscriptions won't work.