LaTeX is designed for typesetting mathematical documents, but it can also be used for posters. It’s not the only option, but it’s pretty convenient if you want to include a lot of mathematics in your poster and/or quickly reuse material from an article. This post distills the advice I usually give students who are making their first poster.
There are several LaTeX packages for posters. I use beamerposter which I think is the most popular. This is great for making a professional poster quickly, but if you want to stand out try something more unusual. I’ve heard some good things about alternatives including minimal-poster and tikzposter but haven’t tried them. See this stack exchange answer for many more options.
A good place to start by editting an existing example such as this template or the one in this blog post by Rob Hyndman. When creating a poster you need to select a theme describing some style choices. The beamerposter package comes with some defaults. For colleagues/students at Newcastle University, here’s a theme including the university logo (created by editting a theme passed down to me by a former colleague.) You’ll need to download the logo separately. The exact file I used is at available here for example. (This logo is probably a bit out of date now. There are some more recent files on the NU maths wiki, if you have access to that. But you may need to play around with image sizes etc. to make it look nice.)
The .sty file used to define a beamerposter theme is fairly easy to edit, and lets you tweak a lot of the appearance options.
An undergraduate dissertation student a couple of years ago improved on my theme file a lot like this but sadly I never got hold of his code!
For more on beamerposter, here’s a journal article on using it, its Comprehensive TeX Archive Network page and its github page. Finally, here are some tips on how you can recycle your used fabric poster into clothing.