When you want to sell your two wheeler then its registration in the RTO office will be transferred in the name of buyer and for that you have to give to the buyer the vehicle registration book along with road tax payment documents (which are generally endorsed in the RC book itself), insurance papers, PUC certificate or token, duly filled and signed in forms 28, 29 and 30 for ownership transfer, NOC and intimation to RTO respectively.
Please keep a copy these documents for your reference before giving all these to the buyer. Practically what happens that the buyer goes to RTO office and submits all the documents there for change of registered ownership of the vehicle in his name.
Likewise he also approaches insurance office for change of insurance to his name.
Knowledge is power.