Is it possible to enter a bill manually after it has been deleted?
Yes, You can post voucher in BUSY if being deleted in data by follow these steps:
Step 1: Go to transaction section then select the required voucher type like sales, purchase etc.
Step 2: Choose add tab then create the deleted voucher with all the details like voucher number, party name, item details etc.
Step 3: After post entry, you can save the invoice.