Dear Rahul,
Chargeability of commission under different heads of Income, totally depends on nature of commission. All the detail are not provided in your question Hence there may be following situations:-

1. If the person receiving commission is employee of the company and receiving commission on sale of products made by him at fixed percentage and it is paid as per employment contract. Employer and Employee relationship should be there then commission is taxable under the head ” Salary”. As per section 17(1) of income tax act, Salary includes:-
   a) Wages
   b) Annuity
   c) Pension
   d) Gratuity
   e) Fees, Commission, Perquisites, Profits in lieu of or in addition to Salary or Wages
   f) Advance of Salary
   g) Leave Encashment
   h) Annual accretion to the balance of Recognized Provident Fund
   i) Transferred balance in Recognized Provident Fund
   j) Contribution by Central Government or any other employer to Employees Pension Account as referred in Sec. 80CCD
2. If the person receiving commission is engaged in Agency business andcommission is received as a part of conducting any business on a regular basis and where the major source of income of the assessee is from such commission income, Then commission is taxable under the head “PGBP”.
3. If none of above situation i.e.the person receiving commission is nor involved in any agency business and niether an employee then commission will be taxable under the head “Income from other Sources”
    

If your situation is not covered in above three then please comment to get specific reply . Further which ITR form is required to be filed for commission income, it also depends on many factors like any income from house property , capital gain etc. In the absence of such information we assume then the person is not having any income other than commission income. Then in case of 1 & 3 above the person may file income tax return in Form ITR-1 but in case of 2 above, the person receiving commission is required to file ITR-3 because a commission agent is not eligible for Presumptive Scheme of Taxation U/S 44AD, Hence He cannot file ITR-4.
Businesses not covered under the presumptive taxation scheme of section 44AD
The scheme of section 44AD is designed to give relief to small taxpayers engaged in any business, except the following businesses:

• Business of plying, hiring or leasing of goods carriages referred to in section 44AE.

• A person who is carrying on any agency business.

• A person who is earning income in the nature of commission or brokerage