The image seen in the mirror is a light-print, not an actual reflection. This is caused by light reflecting off of the mirror's surface. Mirrors have a smooth surface that reflects light without disturbing images. This is known as specular reflection.
Lateral inversion in a plane (flat) mirror means the apparent reversal of left and right in the mirror image compared with the object. Lateral means "sideways". ... Consider your own mirror image. You don't easily perceive your front and back as reversed even though that is what happens when you face a mirror.
Cause of lateral inversion: In a plane mirror, the image is as far behind the mirror as the object is in front of it and that the front of the image and the front of the object face each other. This is the cause of lateral inversion in plane mirror.
The laterally inverted image of the word LEFT is as shown in the figure above.
The images of symmetrical letters like A, H, I, M, O, T, U, V, W, X, Y, 8 are not affected by lateral inversion.