Hello, when topping up fiat currency, you need to provide proof of legal income from funds. Common supporting documents include:

• Work contract: Shows your employment relationship and source of income.
• Proof of tax payments: Such as a recent tax return that proves that your income has been taxed in accordance with the law.
• Screenshot of Brokerage Withdrawal Record: Shows the record of your withdrawal of funds from your securities account.

Please provide corresponding supporting materials according to your actual situation to ensure the legitimacy of the source of funds.