How can I save IT on maturing RD of 10 years

Whether the daughter attained majority now?

No, she is still minor.

Whether you as guardian were/are filing your ITRs?

Let me give you some more info. We had to open this RD as per law and court direction for our adopted daughter until she turns 18. Unfortunately we can not renew the RD 10 years. So the maturity amount will get added to our savings account with tax implication and we will have to open new RD in the name of daughter for remaining years until she turns 18 and the entire proceeds will be added to daughter's account.

Moreover, we as a parent both file ITRs regularly.