So my daughter is 3 years old and she goes to the bathroom just to pee here and there but I can’t get her to let me know when she needs to go. She won’t even poop in the toilet
Some kids are intimidated on how big the toilet is for them. Have you tried buying a small replica of a toilet. Take her with you while you use the restroom and have her sit on hers while you sit in your throne.
Is she still in diapers? If so, she sees no reason to switch to the inconvenient toilet when diapers are so easy. She doesn't need to stop playing to go, so why would she. I would take the diapers away and tell her you ran out and it's time to go in the potty you WILL have accidents, but when she realizes diapers are definitely not coming back she will do it. If you need to use for night time then tell her they are special night time only ones and only put on right before bed.
My daughter would pee in the potty if we put her on there, but would not poop. She would hold it for days. It is different for them to go poop on the potty and this seems normal. We did tell her she could have a piece of chocolate if she pooped on the potty. It helped a little. After 5-10 poops in the potty it stopped being a big ordeal. I will say that they are not used to sitting and pooping so sometimes she thinks she has to go, will sit there, then nothing will happen and she will want to get off. This sometimes happens a few times before she actually goes. It is frustrating, but you got to stay calm and patient and play the game so they dont get more stressed out about it.
And our school did say to just switch to underwear. There are some accidents to deal with, but if you keep the diapers on, there is no "consequence" for them to just go. It will push them to learn to know when they get "the feeling".