You can check your Mac's remaining storage space by clicking the top left corner's Apple icon, About This Mac, and the Storage tab. Occupied storage space is categorized visually. Click the Manage... button for more storage categories in the left panel.
Unfortunately, the System category does not provide more specifics to help you free up space if your storage space is running low.
For a great breakdown of disk usage, I recommend using Disk Drill (free to download and use), which intuitively presents and frees disk usage under its Clean Up tool.
In Disk Drill, the Clean Up tool shows a breakdown of folders and files by the amount of space they occupy on your hard drive. Sorted by decreasing size, larger items are easy to find and purge. You can also mark files for deletion straight from the app.
Happy cleaning!
This was tested and working on macOS Mojave, macOS Catalina, and macOS Big Sur. Need this, but for Windows? Refer to this guide
