Knee wraps can be a uneasy subject for the powerlifting purest, but in my eyes the sport has evolved and they are here to stay. So why not learn as much as you can about them and maybe even try them out!
So why use knee wraps? Well if you can learn to use them properly, you will be able to lift more in them (in the squat)! There is a little bit different technique to squatting in wraps compared to without. What you have to realize is that the wrap is going to bunch up behind the knee and give you the feeling of "hitting depth" when you may not get there. You will have to then "push" through the wrap binding up to achieve depth. This is the most common mistake I see when lifters are new to wraps. They have to learn to "push" themselves down in the squat when without wraps the body is able to get to depth without an active push downwards.
There are many different styles, strengths, lengths, colors, and manufacturers, of wraps - so where to start? Start by finding someone who has experience with them and let them guide you. Have them wrap you the first few times and adjust the tightness so you can really understand what it is like. 10/10 tightness on a cranked knee wrap is nothing comfortable and most are not ready for that discomfort. But when first starting out, start with a light (maybe 4/10) tightness wrap just to begin to feel how you will have to adjust your technique. I would also lean towards using a more basic, stretchy wrap at the start. There are really 2 main categories for wraps - stretchy and stiff/casting. It really comes down to lifter preference and ability to what wrap one should go with. Typically a stiff/casting wrap will have more stopping power at the bottom while a stretchy wrap will give the lifter more rebound out of the hole. As far as length and manufacturer - length can depend on your federation (as 2.5 meter wraps are pretty widely accepted and 3 meter not as much) and for manufacturer just try different ones out and find what works best for you.
How to wrap:
Here is a video of what I find to be one of the easiest ways to self-wrap your knees. The tie at the top allows for an easy finish to the wrap job and once done squatting a quick exit from the wraps.It is easier to self-wrap with a stretchy wrap compared to a stiff as you cannot get enough power wrapping yourself as you can when having someone else wrap you (or you wrap someone else).