In my invoice template, there is a "Product/Service" field with a drop down menu. How can I delete an item in that drop down menu that is not used?

Greetings, @geoff7.

You can only inactivate products or services in your QuickBooks to remove them from the "Product/Service"drop-down menu. I can guide you how.

1. Go to the Gear Icon.
2. Select Products and Services.
3. Locate the desired product or service you want to make inactivate.
4. From the Actions columns, click on the Edit drop-down menu.
5. Choose Make inactive in the drop-down list.
6. Click Yes to confirm. 

Once completed, the product or service will no longer be included in the reports nor displayed when creating an invoice or any sales form. However, it will show as  "Name of the item (deleted)" in your existing transactions.

For more insights about managing your products and services in QuickBooks, you can check this article: Remove or merge a product or service.

Also, you may read through these articles to learn more information and guidance about Product and Service types

• Group your products and services into different categories

• Change the account for a product/service item

• Change Product and Service types

Get back to us if you have other questions about creating creating an invoice in QuickBooks. I'm always here to help.