When you create a custom web content structure you can include a field of type 'Link to Page'.
However you can't use this fields when mapping fields in a fragment.
Since a 'Link to Page' can include both the name of the page as well as the link to the page it would be nice if you can use either one of them. If only one is possible I would probably start with the link. Then you can start using this field with e.g. a CTA button.