Yes, David, one of the types of access you can grant to a user to customize an invoice without giving them full access is a custom role.
Please note that the customer role feature is exclusive to QuickBooks Online (QBO) Advance. If you are using this version, here's how you can create a Custom Role:
- Log in to your QBO account.
- Click on the Gear icon and select Manage Users.
- Enter the user's First Name, Last Name, and Email Address.
- Click on + Add New Role, then enter the desired Role Name.

- Customize the Role Permissions to define what the user can access and perform.
- Once you've completed the setup, click Save to finalize the changes.

For more information, you can check out this article: Add and manage custom roles in QuickBooks Online Advanced.
If your current subscription is under the Essentials or Plus plan, you can use the Standard limited for customers and vendors role.

You can refer to this article to find out what a user can do in this role: User roles and access rights. Please note that this role may or may not be assignable to new people after May 2024.
Feel free to reply to this thread if you need further assistance with any QuickBooks concerns.