If one in the state of Ihraam commits one of those forbidden things, he is given the freedom to choose to slaughter a sheep and distribute its flesh among the poor of the Sanctuary, feed six needy persons at a rate of half a Saa‘ each, or fast for three days. This is called the ransom of ailment. It is mentioned in the statement of Allaah The Almighty (what means): {And whoever among you is ill or has an ailment of the head [making shaving necessary must offer] a ransom of fasting [three days] or charity or sacrifice.} [Quran 2:196]

It is noteworthy that if one in the state of Ihraam repeats the same forbidden thing several times before expiation, like cutting his nails more than once, for example, one ransom is due. But if he commits different forbidden things, like cutting his hair and covering his head, for instance, then, a ransom for each is due. That does not include the penalty for killing game, according to which expiation for each game is due, even if they are of the same kind.

Those are the rulings of ransom that ensue from committing one of the forbidden things during the state of Ihraam. As for the ransom for leaving a duty, like the failure to assume Ihraam from the Miqaat, the failure to combine both night and day in standing at ‘Arafah, the failure to spend the night in Muzdalifah and Mina, the failure to perform farewell Tawaaf, to the end of this series of the duties of Hajj, slaughtering a sheep is due. If he could not find it, then to observe fasting is debatable. Some scholars are of the opinion that he should observe ten days of fasting analogous to the case of not offering the slaughtered animal of Tamattu‘. Others do not make fast binding on him.

But it is necessary to note that if a pilgrim left one of the duties of Hajj, ransom is due on him, whether he left it intentionally or forgetfully or ignorantly, for he has left a rite, unlike committing one of the things forbidden during the state of Ihraam which were previously mentioned, ignorantly, forgetfully or forcibly, in which case, nothing is due on him, according to the right opinion, in view of the statement of the Prophet, sallallaahu ‘alayhi wa sallam: "(The sin committed by) mistake, forgetfulness or under compulsion is removed from my Ummah." [Ibn Maajah and others]

If a pilgrim is performing Hajj At-Tamattu‘ or Al-Qiraan, and is not living within the area of Al-Masjid Al-Haraam, a ransom of an animal to be slaughtered is due on him, the least of which is a sheep or one-seventh of a camel or one-seventh of a cow. That slaughtered animal is offered by way of gratitude. If he could not find it, he should fast for three days during Hajj and seven days when he returns home, due to the statement of Allaah The Almighty (what means): {whoever performs ‘Umrah [during the Hajj months] followed by Hajj [offers] what can be obtained with ease of sacrificial animals. And whoever cannot find [or afford such an animal] - then a fast of three days during Hajj and of seven when you have returned [home]. Those are ten complete [days]. This is for those whose family is not in the area of al-Masjid al-Haraam.} [Quran 2:196]

Ransom also is due on him who has missed Hajj after assuming Ihraam with the intention to perform it, or him who was prevented from performing it by any of the impediments that detained him from reaching the Sanctuary. This matter has details which we have clarified in the rulings of missing or being prevented (from Hajj); and Allaah Knows best.

https://islamstory.com/en/artical/1824/miscellaneous-questions