Topic links:

These links create "jumps" to other help topics, which can be in the current help project or in other help projects or help files.

Topic anchors:

Anchors are not really links in their own right – they are "targets" for other links. They allow you to create a links that go to specific positions in a topic instead of to the top of the topic.

Internet links:

Links to HTML pages on the World Wide Web or email addresses.

Figure links:

Creates a live reference link to a figure or table counter object, including the current caption and number of the object.

File links:

Links to external files on the user's computer.

Script links:

These are not really hyperlinks in the real sense of the word. Instead of taking the user to another page or topic, clicking on them executes script code that you insert.

Named destinations in PDF:

In PDF files, "named destinations" are the equivalent of anchors, i.e. named targets that you can jump to with hyperlinks, like anchors in HTML files. Help+Manual inserts named destinations for a number of targets in the PDFs it creates.

Named destinations are a special case and must always be linked to using file links and a special anchor-like syntax.

See this topic in the help for details on using and linking to named destinations in PDF files.