What is the difference between Canon's fixed-point focusing and single-point focusing? Which one is commonly used?

Single-point focusing refers to one-point focusing, and fixed-point focusing can be one point or multiple points. Single-point focusing is suitable for still photography and composition, suitable for most shooting scenes, but it is not conducive to beginners and easy to cause defocus. Fixed-point (multi-point) focusing range is larger, which is convenient for snapshot and suitable for high-speed moving objects and emergencies. Because of the large focus area, the success rate is relatively improved. However, it is impossible to determine the specific focus, and the focus area may not achieve the expected results in advance. Skilled people pay more attention to one point, including themselves.