What was the method by which "Mut'ah" marriage was conducted before its prohibition? And was it without witnesses or a guardian (wali)? And what is the difference between it and prostitution if that was the case?

The prohibition of Mut'ah (temporary marriage) was gradual. Allah Almighty permitted it for the wisdom of facilitation, and what Allah has permitted is not considered an abomination. Mut'ah was later prohibited and became considered aszina (fornication/adultery) after its prohibition. Its permissibility was limited to travel during military expeditions for ease, and it was not permissible for those residing at home. It did not require the conditions of permanent marriage, such as witnesses and a guardian, but it differed from zina in establishing lineage and the prohibition of marital affinity.