If to answer "How to insert a named hyperlink anchor in InfoPath?" then you can't because Infoapth forms are not HTML webpages (from client Infopath side).
Instead of link one should use a button and formatting rules for this. If you want to appear it as a link, then remove borders, shading, changethe font color and underline.
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Answering comment-question:
You can use (probably also set hidden controls) SelectText and SelectNode in codebehind, see MSDN article:
Note this is accessing data and through it jumping to their visual representations (or rendering containers) - controls to which data fields are bound. There is no way to access controls, i.e. visual representation and rendering objects , in Infopath (client) codebehind, only their data.
It is always helpful to remember that Infopath forms are XML-based, with XML for data and forms being used externally and by various disparate (and incompatible) services in various rendering formats (in order to avoid frustrating requirements and wishes of pulling yourself up by your own hair).
Update:
This is obvious underdevelopment in Infopath since, for example, MS Offcie Words .doc (.docx) documents are enabled to have a bookmark and link a hypelink to it (to jump/navigate to other parts of ta Word document).
Another approach (and probably for using the Infopath data forms from browser only while browser-enabled forms can be also opened in client/Filler) would have been to tweak Infopath template XSL files content (by your own custom XSLT rules) though it will be a maintenance nightmare since it is not supported OOTB and this results in necessity to tweak repaet those tweakings after each editing of template in Infopath Designer or discontinue editing in Infopath Designer at all.