Page Break block
The Page Break block is a simple block which you can add to break your content into multiple pages for the visitor to click through. This can be very useful if you want to separate elements of content (multiple steps in a process, for example), but keep all of the content on one page or post.
Within the editor, the Page Break appears like this, to indicate where the page breaks will be inserted in the front end:-
The Block Editor handles all of the paging management after one or more page break blocks are added.
The paging is a paragraph with class post-nav-links, which can be used for styling. This is different from the other navigation links, so styling can be targetted at this paging without interfering with styling of other navigation, such as previous or next post.