Can I change receivables from head to sub-receivable account and how?

Hi, Kamal. QuickBooks Online (QBO) creates a single default Accounts Receivable (A/R) account at setup to record customer invoices, sales receipts, and payments, helping keep your books organized from the start.

While you can use sub-accounts, QBO will only post to the specific account currently designated as the default. If the parent is the default, transactions stay there. However, if a sub-account is the default, they post there instead.

If you want to group or divide your receivables, you can refer to:  How to group Accounts Receivable or Accounts Payable account types in QuickBooks Online.

Let me know what you're aiming for, and I'll tailor the steps accordingly. I'm ready to help with the next actions.