Fixed layout is a type of EPUB file where the content is laid out in a specific way and cannot be changed by the reader. This is in contrast to reflowable layout, where the content can be flowing and adapt to different screen sizes.
One advantage of fixed layout is that it can be used for richermedia content, such as comics and graphic novels. The content can be laid out in a way that makes sense for the story, and the reader will have a better experience following the story.
However, fixed layout can also have some drawbacks. One is that it can be more difficult to create, since the content needs to be laid out in a specific way. Additionally, fixed layout files can be larger in size than reflowable files, and they may not work as well on all devices.
If you're thinking of creating an EPUB file, you'll need to decide whether fixed layout or reflowable layout would work better for your content.