I want to know more about the "void" option.

Greetings, Samer! I'm delighted to see you here.

When you void a transaction in QuickBooks, you still have a record of the transaction, but it won't affect your account balances or reports. 

In addition, reactivating a voided invoice in QuickBooks Online is unavailable. To recreate the same invoice, you can utilize the Audit log. It has all the information you needed to make a new one. 

Here's how: 

1. Navigate to the Gear icon in the upper-right corner.
2. Click Audit log. 
3. Select the Filter drop-down.
4. Choose the date range. 
5. Make the necessary changes, then click Apply.

Moreover, I'll be sharing the following articles to help manage your invoices in QBO:

•  How to record invoice payments manually
• Send them a reminder message.

Keep me posted if you have further queries about reactivating voided invoices in QBO. I'll be around to help. Stay safe!