How to organize acceptance and automatic payment on the site?

Question

Law in IT

There is a website site texts. The customer enters the money and receives it on the account.
Then other users, let's say, fulfill the client's order, the service subtracts the percentage for the service, and gives the rest of the money to the user.
Then the user orders a payout to the wallet.
So at first it is planned to make payments in manual mode.
What is the best way to receive funds on the site? Provided that the site does not have initial funds for withdrawal, the withdrawal will be from the money that was entered by the customer.