I cannot find any such Place in ITR. The tabs are: Income Details, TDS, Taxes Paid and verification, 80G.
In Income Details Tab, there is a row to enter "Income from Salary / Pension (Ensure to fill Sch TDS1)
on which only one value can be entered. Cannot find any option to enter allowances.
Let us know if you are trying to file taxes from InvestmentYogi. If yes, please select the salary from form 16 option. In the concerned page, you can enter all allowances in the allowances field.