Shawl pins are for knitted, crocheted or loosely woven garments. They should not be used on silk or any other fabric where a permanent hole would form.
I made several different styles, but the easiest one is made exactly like the previously published flower-link bracelet ( https://www.wirejewelry.com/jewelry_making_patterns_tutorials/Wire-Roses-Bracelet_380.html). I use 14-gauge wire for these pins, as opposed to the 16-gauge for the bracelet. The length of 14g wire needed depends upon the size of the loops and the center flower size. I used 12" for the pin on the left and 10" for the one on the right. When hammering the loops, I like to give them a slight curve which makes them easier to use on a garment.