25 % Goods you Can not sold on delivery challan and never sell with only on delivery challan , If you are making taxable as well as exempt supply then you have to issue invoice .
25 % sold goods is your Direct income so , same will be on the Credit side of profit and loss account so entry will be.
Trade Debtors A/c Dr
To Sales A/c Cr
( Goods sold during the period)
Show Sales A/c under Direct income P& L Account
Trade Debtors under under Current Assets Balance sheet.
Always Issue Invoice . Delivery challan is used only when you are sending goods for Job work.