Hi Tee, consistency is the rule here. Every mother is a victim of this. Just the same way a child learns other important things, she will eventually learn this as well. But you have to keep teaching her.
Be familiar with when she is likely to poo next and take her to the potty even if she doesn’t poo eventually. Also, make sure she sits on the potty every morning, an hour after eating and every evening before going to bed.
Don’t hesitate to tap her as a form of discipline whenever she poos on herself reminding her she needs to use the potty.
Any other suggestion? Mummies in the house please share.