That's a really good question.
According to W3Schools, it's done like this:
Jump to the Useful Tips Section
I'm using friendly URLS, so it looks like it's not possible.
Hi!
I have tried making a link to another page and added a bookmark reference in the link. Is seems to get lost however, when saving the page. My guess is that our dynamic link handling does not save the bookmark section of the link. I'll have to investigate if this is something that we should support.
Regards
Linus Ekström
EPiServer Development Team