Please follow the below mentioned steps to cancel the Invoices in bulk.
Step 1 : Please go to Sales >> Invoices >> Click on Actions button >> Bulk actions.
Step 2 : Select the documents, Click on Cancel Invoices.
Step 3 : Click on Cancel button to confirm.
Note: You can follow the same steps, to cancel the documents like Sales return (Credit note), Purchases, Purchase Order, Purchase return (Debit note), Quotation, Pro forma Invoice and Delivery challan in bulk.