The first two of these are enabled from the user settings by enabling the experimental functions (manifested as additional buttons in the project managing view), while the third is likely to be used more heavily to the extent that it is readily available.
Any solution that has been prepared for online reading can be made into a PDF version with a single click of relevant button. The resulting PDF will contain a separate cover page, all collections of writings in their own parts with all printable contents. Page numbers in the footers with section information and before/after appecialpages are included. Images will be as well positioned as on the web, font choices are exactly right and otherwise results are generally just fine. Currently it is preferred to use content list type of "plain structure" as others like "presentation page" and blog-like would give unexpected results.
"CSS module specifies how pages are generated and laid out to hold fragmented content in a paged presentation. It adds functionality for controlling page margins, page size and orientation, and headers and footers, and extends generated content to enable page numbering and running headers / footers." (CSS Paged Media Module Level 3. W3C Working Draft, 18 October 2018.)
Creating a PDF version works well when targeting paper size of A4, but for other sizes the implementation is still under consideration.
Many browsers have not implemented this standard and that is why printing directly from the browser does not provide optimal results as such, when the purpose is to include page numbering etc. E.g. the Firefox browser does not make much use of CSS Paged Media (since last tested), but Edge and Chrome do. However, a problem with using them is that they either include extra information like the date in the header and footer, or the header and footer contents have to be completely empty (the printing settings only have an either/or option).
Actually, as the external service that is supposed to be used for generating PDF files requires a fee to be paid, process is decreased by a one phase so that a user is served with a downloadable HTML file that contains all the mentioned "ingredients" and content. User can then use a browser to print it, if the browser has enough support for the CSS3 Paged Media.
It is possible to export a solution contained in the project into a zip file, so that the contents of that package can be copied via FTP or SCP to a directory on a server of one's choice and be made publicly viewable in a browser. A solution exported this way wouldn't have differences in its outlook, but the contents would be completely "static" (not generated separately at every page load). The images in the work can be distributed via a CDN service, retrieved directly from that another server by the browser or they be contained in relevant web pages as encoded adata.
When preparing a writing and its images for publishing elsewhere, such as in a discussion forum or a Facebook group, writing and its images can be exported to a zip package containing three different versions of the writing. One of them is an unstyled HTML version with tags p, h1 and h2 (lists are converted to text paragraphs). The other two are plaintext, with the difference that one does not have a blank line after the text paragraphs, which can streamline workflows, e.g. when copying and pasting. Pictureshows' image filenames are named in a way to make it easier to identify which ones belong to the same pictureshow. The feature is available in the "text editing" view by selecting "Export for use elsewhere" from the editor's menu.