Dredging is coating something, usually meat, with a flour before browning the item.
The purpose of dredging is to make a meat’s surface a more attractive brown colour, and to create flavourful carmelized  flour bits in the pan that can be used in making a thick sauce through deglazing. It’s a myth that it seals the surface of the meat to keep the juices in. Nothing does this short of dipping the meat in a gallon of varnish.
In dredging, meat such as beef, chicken, turkey, veal, or pork is coated in a flour and then browned in a pan. It can also be done to fish or seafood.
To dredge meat, dry the meat slightly between pieces of paper towel before. This will help it to brown more quickly when it comes to that part, and stop great clumps of flour from sticking in various parts. You just want a light coating of flour.
The flour used is generally white wheat flour, but other items such as breadcrumbs or cornmeal can be used. Whole wheat flour is very flavourful. Whatever the coating matter, it can be seasoned first, or not. To coat the meat, you can toss it with the flour in a plastic bag, a paper bag or in a plastic container with a lid. Or, you can simply put the flour onto a plate, and roll the meat around in it, pressing it into the flour.
When done coating the meat, shake off any excess flour, as it can burn. Then, you brown the meat quickly.
 The carmelized bits aren’t actually carmelized, and aren’t created through caramelization. They occur as a result of a Maillard Reaction.
The hard part in dredging is always gauging how much flour you will need. Any flour remaining after use must of course be discarded, as it’s had raw meat in it, so you want to try to use only as much as you need in order not to waste flour.
There’s no magic; cooks of many years still get it wrong, finding themselves either having used way too much flour that they just have to discard, or trying to figure out how to safely touch the flour scoop with hands sticky with raw meat juice to add more flour.