This article explains what Other storage is on a Mac and how to clean it up.
How to remove 'other' files from your Mac
Your Mac helpfully categorizes files into several broad containers, including Apps, Photos, Movies, Audio, and Backups. These categories are easy to understand. For example, files in the Photos section are clearly photo files like JPEGs and PNGs, and your iTunes library probably takes up the lion's share of the Audio category.
By including an Other category, Apple is able to simplify their storage report and keep everything looking nice and organized. The problem is that the Other category, also known as “other volumes in container” depending on your version of macOS, contains literally every file type that doesn’t fit into any of the other categories.
Some of the most common files in the Other section are:
