Journal Entry of credit note

 Either it's a discount ......so you should booked it as a discount .Now your entry should be like this

Taxable Amt.    - 12000

Cgst                -   1080

Sgst                -   1080

Discount        -     -500

total               

Pass first entry - press F8 ( Sales) in Tally prime

Trade Debtors A/c Dr 14160
To Sales A/c Cr 12000
To Out put CGST A/c Cr. 1080
To Out put SGST A/c Cr. 1080
( sales booking entry)

Credit Note press ( Alt- F6 ) Also you have to mention original Invoice no and date .

Sales Return A/c Dr
Out put CGST A/c Dr
Output SGSt A/c Dr
To Trade Debtors A/c
( sales return entry)

please inform credit note of 500/- is inclusive or exclusive CGST and. SGST .

Cn 500 is scheme amount provided for sales

Ok , If  no  GST  involvement  then  press  Alt F6  in Tally  prime  and  pass entry for Credit  Note 

Sales Return  A/c  Dr 

To  Trade Debtors  A/c  Cr 

(  Sales  return entry ) 

You have mention  Original  Invoice number   and  Date  in Credit  Note  

Mention  in narration that  credit  note of Rs 500/-  is  for  scheme  amount  provided  for  Sale  

Just pass a credit note entry and how hard can it be?