Yes, both Windows computers and Macs work. QGIS (www.qgis.org) is available for all platforms, although it seems to be simpler for Windows users.
Chromebooks do not work because you cannot install applications on these computers.
When it comes to computer performance, general advice applies. Newer computers with a lot of RAM (4+ GB), modern CPU and a fast SSD disk work better than older computers with less performance. However, these can still work, especially during these introductory courses.
If you want to run heavier analyzes and more comprehensive data, you can consider an upgrade in the long run. It is best to test the installation of QGIS and see if the program starts. You should expect about 10GB of hard disk space (a few GB for the program and a little margin for analysis and data).