Public provident fund is one of the best investment tools that provides safety, compounding and tax benefits in one package. This should be the first investment that one gets into immediately after turning 18. The account is meant for a period of 15 years but can be extended by 5 years @ tenure expiry.
The safety of government assurance and the compounding effect will definitely take care of your retirement needs. You can invest up to 12 installments a year and up to 1 lakh in this account every year. You should try to invest the maximum amount possible in PPF account every year.
The following articles provide a great insight into " why investing in PPF is a must?"
PPF account can be opened at SBI bank branches or at your nearest post office. Selected ICICI bank brnaches also provide PPF account facility.
If you are looking for comparing PPF with EPF and NPS, here's another write-up.