The shoe clips have clips with small hooks on the back. These can be easily opened and closed again. This allows you to easily and flexibly attach the shoe clips to many places on your shoe, wardrobe or bag.
Yes, the shoe clips hold securely and firmly thanks to the clip with a small hook on the back.
No, the shoe clips will not damage your shoes. They do have a small hook on the back to keep the clip in place, but this won't damage your shoes. Likewise, you will hardly feel wearing shoe clips and therefore they won't hurt your feet.
Shoe clips can be attached anywhere they can be clipped. This is primarily on shoes, of course, but the clips can also be attached decoratively and flexibly to belts, bags or wardrobe.