What is the ruling regarding a husband telling his wife, "If you leave the house, your divorce paper will reach you," when the wife does not leave at that moment, and does divorce occur if she leaves later? How should she act to avoid the occurrence of divorce while needing to leave the house?

This statement from the husband is a metaphorical divorce (kinayah talaq (definition)), and the occurrence of the divorce depends on the husband's intention. If he did not intend divorce, it does not occur. If he intended to make the divorce contingent upon your leaving the house door, then it occurs upon your departure. The extent of the contingency, whether it is specific to a certain day or applies to all days, also depends on the husband's intention. If he had no intention regarding this, then reference is made to the reason for the oath. The apparent reason here is the quarrel and anger. Thus, if you leave at a time of reconciliation and forgiveness, the divorce does not occur. One must be wary of obsessive thoughts (waswasa).