Hi there, @ushuaia_22.
Thank you for reaching out on this and welcome to our community!
Before an invoice is paid, it's the best time to add it to a project. When you add a paid invoice to a project, the linked payment is removed from the invoice. This will also change the invoice’s status to unpaid. You’ll need to follow the steps to reconnect the payment to avoid accidentally charging customers twice.
We don’t recommend adding invoices linked to more than one other transaction, billable expense, or timesheet. If you add a linked invoice to a project, only the invoice is added. You’ll need to add the linked transactions to the project and reconnect them to the invoice.
You can add existing estimates to projects as long as you haven’t converted them to invoices.
For more information on projects in QuickBooks Online, please visit the link down below:
Set up and create projects in QuickBooks Online.
If you need assistance with anything else, feel more than welcome to reach out to the Community anytime. Have a great day!
