You can create a poster from scratch through PowerPoint, Adobe, Canva, Slides, and other design products. Most of these products will also have poster templates in them. It is just a matter of knowing what size you need your poster to be.
Use this page to find resources to assist in creating your own poster. Whether through a template or from scratch these will assist in designing your poster in an accessible and efficient way.
This is where you can find resources with free poster templates. In addition to this many slide decks can be edited to match a poster design that you would want to use. Looking for free slide templates that really pop? Try SlidesGo.
Having a color scheme can help your poster look its best and be more accessible for all your learners. Use the resources here to find color schemes and check their accessibility.
If printing your poster, it's a good idea to do test print of your poster before getting it printed. Colors often appear brighter and more vibrant on a screen than when printed. All printers will have some variations on the color, but this will help make sure it isn't too far off from your needs.
Using images can be a great way to help communicate some of the content of your poster in another medium. If you don't already have a chart, graph, photo, or other image you would like to use you can find images for free (though you should still cite) from these resources. You can specify that you are looking for images that fall under a specific license.
Many design applications will also have images that you can utilize from their own image banks.