The Insert Snippet tool in Write > Insert Object enables you to insert the contents of another topic or a Help+Manual XML file at the cursor position. You can insert topics and files from the current project, from other Help+Manual projects (there are some restrictions in the Basic version of H+M) and from collections of Help+Manual XML files. This means that you can build up a library of reusable content that you can access very easily.
You can insert snippets in two different modes, Copy and Link. Copy mode is like normal Copy & Paste – it pastes the contents of the topic or file at the cursor position and you can then edit it. Link mode creates a live link to the snippet file. To edit the snippet you must then edit the original topic or file, but then it updates automatically in all the places where you have inserted it, even if you are using it in multiple projects.
If you send your project for translation remember to include any linked external snippet files you have referenced, otherwise the translator won't see them!