Is it permissible for me to charge the client for shipping costs and the price of the curtains under the item of manufacturing wages for wooden desks, so long as the client requested it, because he cannot request another disbursement from the government agency?

If the service applicant is authorized to dispose of it, and their action is not a trick, deceit, or unlawful appropriation of money, but rather for the benefit and facilitation of work, then there is no harm in that. However, if they are not authorized to do so and their action is a trick and forgery, then it is not permissible to cooperate with them. The matter in this regard reverts to the regulations and bylaws of their workplace.