Will changes made to the product & services setting affect the past periods' financial statement?

Hello there, @AthirahZ.

Yes, the financial statement for the prior year won't be affected when you change the expense account for specific services in QuickBooks Online. It will only impact future expenditures and transactions.

Here's a guide you might want to check about handling expenses in QBO: Enter and manage expenses in QuickBooks Online.

You can always get back to us if you have other clarifications about expenses, products & services, or QuickBooks in general. We'd be delighted to help. Take the best care!