When you're making an Online/E-payment, then you can use the Transfer in QuickBooks Self-Employed (QBSE). For additional details, withdrawal transactions are categorized as Transfer in QBSE. Thus, both personal and transfer transactions will not affect your self-employment taxes. It'll automatically be excluded from our calculations for estimated taxes or business expenses.
Also, when you need professional advice to be sure on how to categorize a transaction, I recommend consulting an accountant.
Here are a few articles that can give some additional information that can help your business in the future: