Q: What is mujizat, karamat, Istidraj? (Text)
Mujizat: Miracles carried out by prophets. To deny these actions can lead one to kufr.
Karamat: Supernatural actions carried out by pious people. One can accept them, one can reject them. If they are genuinely pious and remain to carry the sunnah as prescribed by our religion, then there would not be a need to deny these actions.
Istidraj: Miracles carried by evil people. They will cure some, make others sick, get you a good job, have another fired at your request, etc. They can look pious, they can look evil. We must not be fooled by them. (We are living in such times of filth.) They perform supernatural actions to mislead people. Examples of such people: people who commit themselves to acts of sorcery, people that utilize the showing an evil eye, Dajjal and the likes.
Allah Certainly Knows Best.