Occasionally, VR users experience an issue where the 'floor' in VR appears to be at waist or head height rather than its correct floor level. Alternately, users occasionally report that their room dimensions appear to be 'off' or misaligned relative to their original settings. These issues can occur after a VR software update and/or after a VR sensor has been moved or bumped.
HTC VIVE/VIVE PRO
To reset your position in an HTC VIVE or VIVE PRO VR headset, please see this article: https://www.vive.com/eu/support/vive/category_howto/resetting-the-play-area.html
Oculus Rift/Rift S
To reset your position in an Oculus Rift or Rift S headset while in an app like Enduvo, please see this article: https://support.oculus.com/200305533724698/?locale=en_US
To reset or re-map your play area, please see this video: https://support.oculus.com/1225089714318112/