Yes, to claim Deduction u/s 80G, doner need donation receipt having mentioned 80G certificate number of donee, otherwise they can't claim Deduction u/s 80G.
80G Certificate Number is mandatory Sir for claiming deduction under Chapter VIA ( 80G ). Only donation made to specified institutes ( specified by IT Department by issuing 80G Certificate ) are eligible for deduction under Section 80G of Chapter VIA of the Income Tax Act 1961.
For example, RAMAKRISHNA MATH & MISSION is a specified institute. They will issue 80G receipt to claim deduction under ITR where their specified 80G number will be quoted.