Do you know how to change the font size of GUI text… ??
Click on the font you want to change the size of in the “Project” pane (e.g. Courier) and then change the font size of it through the Inspector.
I don’t think you can change the font-size of any one piece of text, you have to change it for each font in your project.
Honestly though, that was in the top 5 when I Googled “unity font” - you could have searched that yourself a lot faster than making this post.