Is it permissible for an employee to use a previous video of a client's face for online appointment booking, knowing that the system requires the client to appear directly in front of the camera for identity verification, and this is done to facilitate the process for the client who finds it difficult to complete it themselves?

It is not permissible to resort to deception by using a video of the client instead of their direct appearance in front of the camera. The difficulty of procedures does not justify this, nor does cooperating with those who request it, due to Allah Almighty's saying: "And do not cooperate in sin and aggression," and due to the Prophet's (peace be upon him) saying: "Whoever cheats us is not of us, and scheming and deception are in the Fire."