From this page you can look quickly the basic information about virtual technologies.
Information of virtual technologies
XR
An umbrella term commonly used to talk about VR, AR, and MR technologies. Also suitable for use with future similar technologies.
VR
The user’s field of vision is completely covered by a computer-generated environment. Of these technologies, usually the most immersive. The simplest way to try VR is with a smartphone and an attached accessory (Google Cardboard), but the most commonly used VR Headsets are the HTC Vive, Oculus Quest, or Valve Index.
AR
Computer-generated elements can be brought into the field of view or on the screen over the real world. Most commonly used on smartphones, but there are also smart glasses on the market designed for this purpose.
MR
Slightly similar to AR, but the imported elements may also interact with respect to the real world. The term AR is sometimes used to describe this technology. The most commonly used when talking about Microsoft Hololens glasses, which are the most common devices on the market that take advantage of this technology.