No, it is not mandatory to submit any documents along with the Return. However, the IT authorities have right to ask for original documents if they have any doubts or otherwise.
Your friend can go ahead and fill up the Return showing PPF amount as Rs.70,000/- (if she remembers it correctly) and in the meantime an effort can be made to obtain a certificate from the bank where she has PPF account. The bank is obliged to give such certificate. In any case PPF Passbook is NOT accepted by IT authorities as proof because it can be fudged. mI hope it is clear.
