The angle of incidence is the angle made by the incident ray with the

The angle of incidence is the angle made by the incident ray with the normal at the point of incidence.
The normal line makes $90$ degrees with the surface of the mirror. The incident ray divides this angle into two smaller parts. They are the angle of incidence and the angle between the surface of the mirror and the incident ray.
The angle of incidence is the angle made by the incident ray with the normal at the point of incidence. This is the definition of the angle of incidence. The angle between the surface of the normal and incident ray is the angle $i$.