A virtual tour, a 360° panorama and virtual reality are related terms, but they describe different things. The distinction helps when deciding how to document and present a place.
A virtual tour connects views and information
A tour lets the viewer explore a place through linked views. Those views may be photographic panoramas, photographs, video or a modelled space. Text, sound, maps and floor plans can explain what the viewer is looking at and how the locations relate.
A photographic panorama has a fixed viewpoint
In a spherical panorama the viewer looks around from the position where the camera was placed. Dragging the image changes the viewing direction, not the camera’s position. Hotspots can connect that panorama to another photographed position.
Closely spaced panoramas can make the transitions feel continuous, but photographs alone do not provide free movement through a complete 3D scene.
A 3D environment describes space differently
A modelled or reconstructed environment can allow movement between viewpoints, depending on its geometry and the application. Its appearance may come from photographs, scanning, manual modelling or a combination. It should be clear which parts are recorded and which are reconstructed or proposed.
VR is a viewing mode
A headset can present either photographic panoramas or a 3D environment. A tour that runs in a normal browser does not automatically support a headset. Web-based immersive viewing depends on the application, browser and device; the WebXR specification describes the relevant web interface.
For many projects a useful starting point is a tour that works on an ordinary screen, with clear navigation and links to the wider documentation. See my virtual-tour work and the Museum of Ancient Eleutherna project for context.