Why do we need money as a medium of exchange?

Economic activities explain the transaction that a person makes for satisfying their interest, such as producer sells items to earn profit and consumer buys those items. These transactions need a specific unit to make an exchange that can be accepted by every person in the country. Money works as an intermediate unit while making an economic transaction. Money holds legal doctrine due to which it is acceptable in every location of a nation because the central bank issues it. Without money, trade between the parties become problematic as it requires a double coincidence of interest among them.