Difference between "Write off" and "Void":
|An invoice is written off when you are sure that the customer is not going to pay you and you need to close the invoice.||An invoice is voided primarily to correct errors committed and issue another invoice in lieu of the voided invoice. This way, you can continue to maintain the numbering sequence and an audit trail .|
|The Invoice Details report will show the balance due as nil||The Invoice Details report will show the balance due for the voided amount|
Deleting Vs Voiding
When you delete an invoice, the record will be removed leaving no trace of the invoice for any future reference, also your invoicing sequence will get disturbed.
On the other hand when you mark the invoice as void, it won't be removed from the system and will not be reflected in your sales figures. The invoicing sequence will undisturbed.
When to void an invoice?
Zoho Invoice FAQ