There’s no single, direct answer to this, and pretending otherwise wouldn’t help you prepare for a procedure.
What can be said is about anesthesia, which is the closest thing to an answer. When debridement is done at a wound care center, you may need to have general anesthesia, which means you’re asleep and pain-free, for debridement of a large wound.
That’s for a large wound. It doesn’t tell you what to expect with a smaller one, so don’t read anything into it either way.
One fact bears on the question indirectly. Diabetic ulcers are often painless, because of decreased sensation in the feet. How a procedure feels depends in part on what sensation is present, which varies between people and between wounds.
The methods also differ a lot from one another, which is another reason there’s no single answer. They include surgical debridement with a scalpel, scissors or other sharp tools; a whirlpool bath; washing with a syringe; wet-to-dry dressings pulled off along with the dead tissue; and enzymes applied to dissolve dead tissue. Those are not comparable experiences.
The practical version of this question is worth asking out loud before the procedure, not after: what will be done, whether anything will be given for pain, and what you should expect to feel. Wound centers do this daily, and the question is routine.
Along with the treatment itself, pain management is one of the services a wound care center may provide.