Children education Allowance which is re-reimbursed amount. If it is taken under taxable income, what is the process of calculating income tax?

There is no Children's Education Allowance that I know of in the federal tax system. If it is a foreign tax issue (India, Canada, etc.), this forum deals exclusively with U.S. tax issues.

This MAY be a state allowance, in which case you need to identify the state.