Gift to father / siblings who invest it for income

No. Not taxable. for you.  or for them . 

I hope you know that it was taxable when you earned it. When you transfer to your father and siblings. You will not be levied twice. You should report this to Income Tax while filling your ITR.

When your father or siblings who received money from you can avail tax exemption for their personal use. If they earn money from it as you said FD, Investment so on in their name. You will not be taxable. They have to pay tax for their earnings.

They should also report the money received from you and get exemption from tax. And earned incomes are taxable. Tax deduct by Banker or other institution.

Age of sibling ? 

Age of sibling is 44 yr

How to report in my ITR? Which section in ITR to enter the amount of gift transfer?

Report it under Exempt Income section in ITR1 under Others subcategory.

Your parents need to disclose this in his /her ITR  and in not yours  ITR.

There are multiple opinions here some says you have to report some says no need but no one has the perfect answer .

To me Reporting and get peace of mind if best thing we can do