with the next version of PDF24 Creator, the PDF24 Toolbox tool Add watermark can also use an image, with an adjustable size in percent of the page width. That will be the easiest way to put a logo on every page.
Until then you can try this online: create a one-page PDF that contains only your logo at the desired place (for example from a Word document with just the logo in the corner) and lay it over your pages with https://tools.pdf24.org/en/overlay-pdf
The online watermark tool https://tools.pdf24.org/en/add-watermark currently works with text only. We will add image watermarks for the online tool to our list.