How can i put back "Paid" from "Void"

The way I understand it, you can't unvoid it or "put it back".  You would have to delete it and re-enter it all. 

If it was actually marked as paid, voiding it should have left a credit.  You could always just create a new invoice and use the payment, or credit toward that.  

You are in the right place, noelleviktoria@g.

The change is permanent when voiding an invoice in QuickBooks Online (QBO). Though there's no automatic way to reinstate a voided transaction, however, we can open it. Then, view the information for the transaction and manually re-enter the transaction. Let me show you how: 

1. Find and open the voided transaction.
2. At the bottom of the page, click More.
3. Choose Audit History.
4. Select Show all to see the original details of your transaction, any edits made, and when it was voided.
5. Take note of all the information necessary to re-enter the transaction. The amount of avoided transaction is always zero. Just use the appropriate amount when re-entering the transaction.
6. Select the back button on your browser, then proceed on re-entering the voided transaction.

Once you’ve entered the corrected transaction, your records should update accordingly. Then, record the invoice payments again in your account. You can also follow the steps provided by Just_me in applying the patent to the new invoice. Feel free to visit our Sales transactions page for more insights about managing your customer transactions. 

That'll do it. I'm just one click away if you need a hand with running your financial reports or any QBO related. I'm always here to ensure your success. You have a good one.