It’s often overlooked that 360° photography is always made from more than one image which has been joined together , the process of joining multiple images together and blending the overlapping areas is called stitching.
There is a simple basic theory behind stitching images together in 360° photography. It lays in the ideal concept that if the lens is perfect and the focal point is exactly in the same position and you overlay the two images they will lineup regardless of which direction you point the camera.
Unfortunately lenses are never perfect and it’s very difficult to turn the camera and keep the focal point in exactly the same position. In reality we need to use various tools to deal with any errors that come from the real world of imperfect lenses and cameras.
Significantly, the tools for blending and stitching images have become more intelligent over the past 10 years, what’s really important is the source material. These images below show for 90° views which are stitched together to make the image underneath.