Zoom can be used via a Computer, a Tablet or a mobile phone.
If being used on a computer, it is best if it has a camera and a microphone. (Most laptops have these)
If you are simply joining a meeting, then there is no need to register. Just use the Meeting ID and Password provided.
Zoom can be accessed via a Browser on any of these devices, but may ask you to download the ZOOM App for your device (It is Safe, and simply), to do so).