What does record transaction mean?

Since a transaction is "an agreement, communication, or movement carried out between separate entities or objects, often involving the exchange of items of value, such as information, goods, services, and money," recording a transaction is entering it into the infromation systems of an entity. As virtually all transactions have financial consequences, these transactions are usually entered into the accounting system.

In the accounting system, double-entry accounting is used, wherein an accounting entry involving the debiting and crediting of accounts is recorded in the accounting ledger of the entity.

I hope this helps.