Is the fee charged for electronically transferring money, which is paid before receiving the amount from the customer, considered a usurious loan that brings benefit?

As long as the questioner is transferring from his own money, he is considered a lender to the client. It is not permissible to combine a loan with any commutative contract, such as sale or lease, because the Prophet, peace and blessings be upon him, said: "It is not permissible to combine a loan and a sale, nor two conditions in one sale." So, if the questioner profits from the transaction or takes a fee for it, it is not permissible for him to combine that with lending to the client. Rather, he must take possession of the money first and then transfer it. If the transferred amount is in a different currency than the received one, then he has combined a lease and currency exchange, and currency exchange is not valid unless there is a hand-to-hand exchange.