What is the ruling on helping students solve their exams for a fee, knowing that these are international certificates required of employees and high school students, and some of them cannot afford them?

Permissible assistance, such as explanation and training, may be compensated. However, assistance in cheating is forbidden, and no payment may be taken for it, based on the Prophet's (peace and blessings be upon him) saying: "Whoever cheats us is not of us." This applies to all forms of cheating.