JAR only accepts submissions that are created with the graphical or the block editor. You can use both variants inside a single exposition.
Graphical editor: text and media elements are placed on potentially very large backgrounds requiring readers to scroll across a page to read or view content. Those pages and the locations of your materials do not adjust to the screen or browser window allowing for maximum control over your page. However, pages created with the graphical editor make many expositions difficult to read on smaller screens or mobile devices.
Block editor: text and media elements are placed in rows and columns (‘blocks’), which adjust to the screen size and browser window. This leads to much better accessibility but less control of the relative size and positioning of your materials. (Note that not all features of the graphical editor are already implemented in the block editor.)
Due to the issue of accessibility, JAR prefers submissions created with the block editor for those cases where the page design is considered less important. However, when it is, please use the graphical editor.