How do i map a service to an income account type to prevent that invoice from being a categorized as unapplied cash payment income?

I'd be glad to help change the account for your service item, @vwa111.

You can follow the steps below:

1. Go to Settings ⚙ and then select Products and Services.
   
2. Select the service item and from the Action column, choose Edit.
   
3. From the Income account ▼ drop-down, choose the account you want to use. 
4. If the item has an existing transaction, put a checkmark beside Also update this account in historical transactions.
5. Once done, click Save and close.
   
   

To check:

1. Go to Settings ⚙ and choose Chart of Accounts.
2. From the Action drop-down of the account, select Edit.
3. Change the detail type to Sales of Product Income if necessary.
4. Click Save and close.

I've also added this article that can guide you set up products and services in QBO: Add product and service items.

Feel free to let me know if you have other queries with setting up product and service items in QBO. I'm always available to help you. Have a great day ahead.