Making an Academic Poster (A0 size or custom) with Google Slides
・Using Professional Software to make an Academic Poster
(for a Poster Presentation) can be expensive, free software can also do it.
・Google Slides, Google Sheets, Powerpoint, Excel can also do it but you'll need to resize your page/slide.
・You can add your own background and shapes to make sections.
・You can save your project/poster as a PDF & PNG also.
・You'll also be able to print as an A0-sized Poster or any custom size
I hope this helps.