I can help change the date format in QuickBooks Online (QBO), kamilya.

We can modify this in the Accounts and Settings section. Please follow the steps below to proceed:

1. Go to the Gear icon.
2. Select Account and settings.
3. Click the Advanced tab.
4. Tap the Other preferences edit pencil icon.
5. In the Date format drop-down arrow, choose dd-MM-yyyy.
6. Hit Save, and then Done.
   
   

Once done, open an invoice to verify the date format change.

I've added this resource to help personalise your invoices and other sales forms in QuickBooks: Customise invoices, estimates, and sales receipts.

You might also want to consider changing your QuickBooks Community username, as it contains your email address, which could compromise your privacy and security.

Keep in touch if you have other concerns about managing your invoices. Doing so helps us ensure everything is taken care of.