How do I categorize a refund from Amazon and one from an insurance company?Also, when recording a loan, do I separate the interest and principle

Hello there, @lilyic2020-gmail.

I'm happy to assist today so you can categorize a refund and appropriately record a loan payment.

First off, to categorize the refund, follow these steps:

1. Go to the Banking tab.
2. Select the tile for the account you want to review. 
3. Click the For Review tab to start your review.
4. Find and click the transaction you want to categorize. 
5. Click on Categorize and fill in other needed info.
6. In the Category field, select the category you want to associate the transaction with. If you're not sure which account/category to use, you can consult your accountant. If you don't have one, you can find through this link: Find an accountant.
7. Once done, select Add.

Your categorized transaction will be shown in the Categorized tab beside For review.

With regards to recording a loan, yes, I agree that we need to separate interest and principle. See this article for more details: Set up a loan in QuickBooks Online.

Additionally, I have here an article that will help you reconcile your accounts so they always match your bank and credit card statements: Reconcile an account in QuickBooks Online. 

Keep your post coming if you need any additional assistance with your bank transactions in QBO. I'm always here to help. Have a great day!