A credit is company money that the company has deposited into your account as a bonus or prize – it is no different from the balance – it also participates in drawdown and trading. But it cannot be withdrawn from your account. Equity is used for trading.
Equity = Balance+Credit+Current Profit. In a certain situation you may have a negative amount on your balance – if there are no open trades, a part of the credit is transferred to the balance at the entrance to the cabinet, restoring it to 0.