OnDemand users are not able to create user macros. However, Atlassian recommends in their documentation to create a Page Break macro in order to control page breaks when exporting content to PDF.
The export to PDF option is used often for creating customer-facing documentation. Not having this control in order to keep text/tables together, text/images together, and avoid orphan headings, creates extremely unprofessional documentation and not a good representation of the company to the clients.
Having this macro out of the box for OnDemand users would allow them to use this key value of using the content without having to use a hack that causes frustration and confusion when other users are editing doc and not knowing how to manage the page breaks; it also creates additional space at the top of the page. The option only available to OnDemand users is to update the CSS to break after a defined header, e.g. h6, and then input text that is h6 and make it white to force a break.