What is the ruling on receiving payment for performing accounting for cafes that sell shisha, shops that sell tobacco and ready-made clothes, and assisting the client in reducing the actual amount of tax that must be paid?

It is not permissible to work in recording and registering accounts for a shisha cafe due to its involvement in aiding sin. Working in a shop that sells both permissible and forbidden items is not allowed if it is not possible to separate the permissible from the forbidden, but it is permissible if such separation is possible. There is no harm in assisting someone who wishes to evade forbidden taxes, but it is not permissible to evade legitimate taxes or to assist in doing so.