Hello Suzanne,
Thanks for posting on the Community.
If you void the invoice this will still show in the records of the account and the figures this was for, if you cancel (delete) the invoice these figures will be removed and also not show when reporting. We would still suggest speaking with an accountant before voiding or cancelling the invoice to see what will be the best way to reflect this for your business.
Please let us know if there is anything else we can help with regards to your QuickBooks accounts.