Can the expense be validated by a certain person?

Welcome to the Community, @zduban.

There are different User Types in QuickBooks Online. You can set restrictions to specific Users so they have access to Expenses. Here's how:

1. Go to the Gear ⚙ icon, then Manage Users.
2. Find the User you want to edit, then click Edit in the Action column.
3. Choose the User Type. Select Vendors and Purchases to work with Expenses.
4. Hit Save.

That's all there's to it! For more information on how to edit, add, or delete Users in QuickBooks Online, click here.

Let me know if you have additional questions or concerns. I'll be here.