When Muslims are involved in a transaction, they must write down the terms of the transaction. They may ask an impartial person to do the writing; this person may not refuse the request as, by doing so, he shows his gratefulness to the Lord who has thought him the knowledge of writing. The debtor will make the dictation and the writer has to fear God and not to cheat. If the debtor is mentally/ physically incapable, his guardians should take care of dictation. two just men should witness the transaction. If there are not two men available, one man and two women suffice for this purpose. That is because, if a woman changes her mind, the other one remind her. The witnesses may not refuse to testify, if called for later. Write down as in detail as possible and explain everything, including the time of re-payment of the debt. The above mentioned process pleases the Lord. If the transaction is on the spot, however, there is no need for being written down but it does not harm to have witnesses. It will be very wicked of you to harass a witness. God, thus, is teaching you; be mindful of the Most Knowledgeable.