If you want to get a head start on translating your projects you can use the built-in DeepL translation system. This advanced artificial intelligence based machine translation is radically better than any automatic translation in the past and you may find it good enough for basic needs or a foundation for proofreading with surprisingly little need for correction.
Your uncompressed XML project files (.hmxp save mode) can be edited and translated directly with an XML-aware professional translation tool like SDL Trados. See the topic on translation memory for instructions.
You can also translate your projects in Help+Manual itself. This can be done either in-house using your own copy of the program or by an outside translator working with Help+Manual as a translation editor. Only the Basic version of Help+Manual is required for this. The Basic version can edit all features of projects created with the Professional or Floating license versions, including uncompressed projects in the HMXP format (it cannot create them but it can edit them). You cannot create some features with the Basic version, but this is not something the translator should be doing anyway, and all features created with the other versions can be translated with the Basic version.
Integrated support for updating translations made with Help+Manual
The Project Synchronization Tool makes it easy to identify topics containing changes in the next version of your documentation so that you can provide the translator with a new version of the project file to update.
While it is possible to edit Help+Manual projects with a normal XML editor it is not something we can recommend. This also exposes all the XML source code and tags to editing and the danger of damage to the code and errors is very high. For good, reliable results it is best to use either Help+Manual itself as the translation editor or a translation memory tool.
This is the simplest solution. If your translator also has Help+Manual (the Basic version can be used to translate all projects, including Professional projects) they just open a copy of the project and translate it, and you then get a translated version back. The Project Synchronization Tool included in the program identifies new text that needs to be translated when you update your projects.
"Translation memory" tools like SD Trados (this is the market leader) automatically "remember" all text that has been translated so nothing ever needs to be translated twice. They can process Help+Manual's XML projects directly, so there is no conversion necessary. When you update your projects all known text is translated automatically and the human translator only needs to handle new and changed material.