Hello, @TAnastasia.

I'm here to help share information about marking expenses as billable.

Changing your account preferences or unchecking the option to mark all expenses as billable won't affect or change the previous items/transactions created. The changes only affect on the transaction/s created after unchecking the Mark all expenses as billable box.

However, marking expenses as billable also depends if the Billable column is manually checked/unchecked.

If you have any other questions about billable expenses, just add a comment below. I'll be always here to help you. On the other hand, in case you have any other QuickBooks concerns in the future, you may also check our help articles: Help articles for QuickBooks Desktop.

Have a great day ahead!