Hello, I voided an unpaid invoice by mistake, how can I undo a void?

Undoing a voided invoice in QuickBooks Online (QBO) is easy, and I'm here to show you how, @vcruz9225.

You'll have to manually re-enter your invoice transaction to undo it in QBO. You can use the Audit Log feature to get the details needed and recreate it with the same invoice information. 

Here's how:

1. Go to the Gear icon.
2. Choose Audit Log.
3. Find the invoice you wish to undo. You can use the Filter option to find the invoice easily.
4. Select the Invoice No. link under the Event column or View under the History column to open invoice details. 
5. Take a screenshot or take note of the invoice details (i.e., name of customer, date, and amount).

After that, you're set to manually re-enter the invoice. You can refer to this article for the detailed steps: Create invoices in QuickBooks Online.

Once your customer pays for their invoice, the next step is to process the payment. To do this, you can refer to this article: Record invoice payments in QuickBooks Online.

Also, you're able to create attractive and professional-looking invoices in QBO. With this, you can add the info that matters most to your business. To know more about this, check out this article: Customize invoices in QuickBooks Online.

Keep me posted if you have any other concerns about managing your invoices and other sales transactions in QBO. I'll be happy to help. Take care and stay safe.