There is no option in Eway bill for debit Note & aslo no option for sale return in case Transaction Type : outward supply. ( if recipient is returning Goods)
If you want return the goods ask your supplier to generate Eway bill By selecting transaction type : inward, & Sub Type Sale Return
Or
If You are genrating , then genrate on delivery challan & accompany the copy of debit note with it Select Sub Type : Others & In remarks type Goods Return