Who can open a Public Provident Fund PPF account?
Anyone can open a PPF account, either on his/her own behalf or on behalf of a minor. Being part of a General Provident Fund or Employees Provident Fund scheme does not disqualify you from subscribing to the PPF, but at no point are you allowed to have two PPF accounts in your own name at the same time. Doing so will invite a penalty: if the issuing authority (bank or post office) detects two accounts during the tenure of the scheme, you will get only your principal back. Also, two adults cannot open a joint PPF account -- an account has to be opened singly, but can have one or more nominations.
It's a good practice to open a separate account in the name of your spouse (or your minor children) and keep contributing to it -- you can even claim the tax benefit from the contribution made to accounts in your spouse's or minor children's names. In this way you could save tax-free funds even for your children and spouse.
Consider opening a PPF account even if you are not a taxpayer, and keep it active. When you do become a taxpayer, you will have an account that will mature early. Remember, however, that any change in the interest rate will apply to you too, even if you've been maintaining an old account.
NRIs who wish to avail of rebate on their income in India are also eligible to open a PPF account. Subscriptions, however, will have to made from their NRO account on a non-repatriable basis.