## How do I adjust the font size?

To adjust the font size for the whole document, you can set a global option in the documentclass - see e.g. https://www.writelatex.com/read/kjbnzqbvqhvr

The default article class is limited to 12pt, but you can go up to 14, 17 or 20 points if you use the extarticle class, e.g.:

\documentclass[a4paper,17pt]{extarticle}