receiving inventory that was pre-paid for.

I got you covered, @shining sea.

Here are the steps you can perform to record the payment for the prepaid inventory. You can write a check to the vendor and record it in your Accounts Payable (A/P) account, reducing the balance until you're ready to enter the final bill.

1. Go to the Banking menu, select Write Checks. 
2. Click Create Check.
3. Fill in the necessary details.
4. Hit Save.

Next, is to enter the bill:

1. Choose the Vendors menu and select Enter Bills.
2. Click the New on the left panel.
3. Enter the needed info and then Save. 

Then, apply the prepayment to the bill. Here's how:

1. Navigate to the Vendors menu, then click Pay Bills.
2. Highlight the bill you want to associate with the prepayment.
3. Select Set Credits.
4. The prepayment will display on the Set Credits screen. Make sure it is checked, then hit Done.

For more details, please refer to this article: Record vendor prepayments or deposits for prepaid parts or services.

I've also added this helpful source, so you can browse topics that can help you with your QuickBooks tasks. To get started head to the QuickBooks for Mac user's guide. 

Let me know if you have further questions in recording your prepaid inventories in QuickBooks. I'm always here to help. Have a good one.