Thank you for posting here in the Community, Tim.

Let's modify the starting date of the item created so you can use it when processing estimates or purchase order (PO).

Inventory items that were added fall before the date you're trying to create a transaction can't be used. To get this fixed, please follow the steps below:

1. Click Sales from the left menu, then select Products and Services.
2. Find the created item and click Edit under the Action column.
3. Under Quantity on Hand, click Starting Value. A message will appear warning not to change this value, select Got it!
4. Change the As of date field to the correct date. This item can only be added on transactions that are dated on or after this date.

I'm adding this article to learn more about tracking inventory in QuickBooks Online: Set up and track your inventory.

Just in case you want to change the product and service item types, here's an article you can read for the detailed information: Change product and service item types in QuickBooks Online.

Keep in touch if you need any more assistance with this, or there's something else I can do for you. I've got your back. Have a good day.