How do I prevent a personal loan to the business from appearing as sales on my VAT return?

You have me to help you manage your expenses in QuickBooks Online (QBO), @Moike. 

Let's review your account details and ensure that it's not associated with any of your sales tax. 

Since mixing personal and business funds sometimes happens, you can record it in QuickBooks. After that, you can reimburse the company. Here's how to do it.

1. Select + New.
2. Choose Check or Expense.
3. Click a Payee from the dropdown ▼ menu.
4. Tap the Bank Account, Cash Account, or Credit Card you used to make the purchase.
5. In the Category details section, select the dropdown menu ▼ to select the tax category that fits your need.
6. Enter the Amount of the purchase .
7. Select Save and close or Save and new.

For more detailed steps, you can check out this article: Pay for personal expenses from a business credit card or bank account

I'm adding these articles for your reference:

• VAT: Getting Started
• Submit a VAT return in QuickBooks Online

Post again if you need more help. We'll respond as soon as we can.