Welcome to the Community, lijiapeng2242.
Could you clarify what type of refund you're requesting? Is is for a product purchase, a subscription, or a vendor transaction? Knowing the details will help us resolve it quickly for you.
If your refund is for a vendor transaction, the process depends on how purchases are recorded. You can check out this article for guidance:
Enter vendor credits and refunds in QuickBooks Online.
Otherwise, if it's a subscription refund, this article can help you understand eligibility and request a refund:
Request a refund for your QuickBooks product.
If you've meant something else, feel free to leave a comment below. We're here to help.