Hey Sai! Family annual income certificate has to be submitted in which total family income is mentioned which is sum of both mother and father's income. You need to submit income certificate when you are going for TFW or EWS tyoe of seat or reservation else income certificate is not needed in any of the counselling. 

If both parents are earning , then you should submit the income certificate for that parent whose income is less in case you want some fees reduction.  But if in case it doesn't matter in your case , you can ask any of your parent to submit their income certificate.  It will be the same. I hope it answered your query 

Your parents income certificate shall comprise of total annual income of the entire family. This income certificate includes the total average income earned by both the parents. In case it does not include the same then you must present the income of your father's income certificate.