'materials' product income account has changed to 'cis income standard 20%' so i cant use it for standard customers. How do I change this back?

Hello there, @manchester-decor.

I understand you want to use material's product to standard customers. However, in QuickBooks Online, once the product income account is changed into CIS income account, there will be no option to change it to other account.

As a workaround, I recommend creating a new service/inventory/non-inventory for materials and choose the income account you want to use. This way, you can use the new product to standard customers.

Refer to this article for the detailed steps: Add product and service items to QuickBooks Online.

I'm adding this article to guide you in changing an account for a product in QuickBooks Online: Change the account for a product/service item.

For future reference, you can read this article about tracking sales tax automatically when making a sale: Use automated sales tax on an invoice or sales receipt in QuickBooks Online.

Feel free to click the Reply button below if you have questions about changing item accounts in QuickBooks Online. I'm always here to help. Have a great day.